LS ENGINE TECH (Part 3)

03

In addition to four vertical main cap bolts, each main cap also features one side-entry bolt per side.

04

The Gen III and Gen IV blocks feature the thrust bearing located at the No. 3 main.

05

The center valley on this LS6 block features two knock sensor bung ­locations.

06

The LS7 blocks feature an easy-to-find cast-in “7.0L” identification on the right front outer wall.

07

Crankshafts feature a reluctor timing wheel. The unit shown here is a forged crank from Callies. (photo courtesy Katech)

08

All Gen III/IV engines feature a front-mount crank-driven ­gerotor style oil pump that is keyed to the crank snout.

09

While early Gen III LS1 engines featured perimeter-bolt valve covers, all later versions use the center-bolt style over. The ­covers shown here are made by Katech.

10

LS1 and LS6 engines feature two different length (short/long) primary head bolts (10mm x 100mm and 10mm x 155mm) in addition to 8mm x 45mm inboard pinch bolts. The LS2 and LS7 engines use the shorter 100mm bolts only, along with the pinch bolts.

11

OE connecting rods for all except LS7 are PM (powdered metal).

12

OE pistons feature a moly/graphite skirt coating, screen-printed onto the skirts.

13

The OE PM connecting rods feature cracked caps for dedicated cap registry.

14
Whenever servicing cracked cap rods, the caps must be kept with their ­respective rods. Katech tells us that for any high performance application, ­superior aftermarket rod bolts should be installed in place of the OE TTY bolts.

15

Pistons require clearance at the pin bosses because of the crank reluctor wheel (only at No. 8 piston, but all pistons are the same due to balance).

16

The LS7 uses forged titanium ­connecting rods as OE. (photo courtesy Katech)

17

LS1 cylinder heads feature a No. 853 casting identification.

LS ENGINE TECH (Part 2)

CAMSHAFTS

All LS series camshafts are of the roller style. The LS series of engines utilize a camshaft timing sensor. To provide a signal to the sensor, 1997-2004 LS engines feature a machined reluctor on the camshaft, located immediately in front of the No. 5 main cam journal. Camshafts from 2005 and later eliminate this reluctor, with cam timing picked up at the cam sprocket.

An incorrect rumor has it that when using the stock valve train geometry, the safe maximum camshaft lift must be kept to 0.570″, since the rockers begin to dig into the valve tips beyond that lift. However, Katech’s Newman told me that this isn’t true, since World Challenge race engines that they’ve built typically feature as much as 0.595″ lift with no problems.

By the way, standard LS series OE rocker arm ratio is 1.70:1. The LS7 features 1.80:1 rockers.

All LS heads feature PM (powdered metal) valve seats and powdered metal guides (this PM formulation provides the lubricity of bronze and the longevity of cast iron guides).

All LS1, LS6 and LS2 heads feature tall cathedral-style intake ports. The LS7, L92 and LS3 heads feature rectangular intake ports.

All LS heads, with the exception of the LS7, feature as-cast chambers and ports. The LS7 heads feature CNC-machined chambers, intake ports and exhaust ports.

According to Katech, all cylinder heads within the LS family are physically interchangeable among blocks, with the exception of the LS7 heads. The LS7 cylinder heads cannot be mounted to other LS blocks, as the wider valve layout would result in valves contacting the bores. Also, the L92 head cannot be used on the LS1. Valve clearance must be verified before performing any head swap.

A variety of OE Gen III heads are available, including an iron small port (initially used on the 4.8L truck engine), the LS1 aluminum head, the LS6 aluminum head with 63cc chambers, the LS4 aluminum head with 67cc chambers and LS6 heads with larger ports and larger chambers.

FIRING ORDER

All LS series (Gen III and IV) engines feature a firing order of 1-8-7-2-6-5-4-3. This represents four cylinder swaps as compared to the standard (Gen I and Gen II) smallblock/bigblock Chevy order of 1-8-4-3-6-5-7-2.

FASTENERS

All OE threaded fasteners in the LS series of engines are metric. There are no imperial-format (inch) fasteners anywhere in the original-equipment build.
All OE cylinder head bolts, main cap bolts and rod bolts require torque/angle tightening.

There are also no NPT threads found anywhere (water jackets, etc.). Instead, straight metric plugs that featured that use O-ring seals.

VALVES

Some engines feature solid stems, while others feature hollow, sodium-filled exhaust stems. The LS7 uses titanium intake valves and hollow sodium exhaust valves.

LIFTERS

All LS series engines feature a roller lifter, and all feature a 0.842″ lifter diameter. Instead of using dogbones or metal finger-trays to locate the roller lifters (to prevent lifter rotation in their bores), special LS-only composite plastic “lifter trays” are used. These trays each hold four lifters. The cylinder block features a large recessed area above each set of four lifters to accept these trays. During assembly or disassembly, the lifters are held by the trays, allowing a complete set of four lifters and their tray to be installed or removed as a set (lifters and tray together).

ROCKERS

All LS series rocker arms are semi-roller type, featuring a trunion bearing at the pivot. All LS rockers are interchangeable for intake and exhaust except L92, LS3 and LS7 rockers. LS7 rockers are unique, as the intake rocker features an offset, and the LS7 rocker ratio is higher at 1.80:1, as opposed to 1.70:1 for all other LS engines.

CYLINDER HEAD GASKETS

Early LS engines featured composite type cylinder head gaskets. Around 2002, GM switched to MLS head gaskets.
All remaining gaskets throughout the engines are formed elastic seal type gaskets that are reusable (depending on condition of course).

PISTONS

OE stock pistons are hypereutectic type. Aftermarket forged pistons are readily available from most piston makers. Depending on the specific crank, LS type piston No. 8 may require a narrower profile at the pin bosses in order to clear the crankshaft reluctor wheel (used for picking up crankshaft timing). This is especially important if a stroker crank is being used. Piston deck height (LS1) is 0.008″ above deck.

VALVE SPRINGS

All LS series heads feature beehive-shaped springs (these feature smaller diameter upper and lower coils for superior damping of spring harmonics). All OE spring retainers are steel, even in the LS7. This single beehive spring design eliminates the need for dual springs, and also allows the use of smaller and lighter retainers.

CONNECTING RODS

All LS rods are constructed of forged powdered metal (PM) with cracked caps, with the exception of the LS7, which features forged PM titanium connecting rods.
While the standard smallblock/bigblock Chevy engine featured an offset connecting rod, the LS series features on-center connecting rods (pin bore in relation to big end bore). DO NOT use offset connecting rods in any Gen III engine!

According to Katech, the OE rods are surprisingly strong, while the primary weak point is the rod bolt. Changing to high performance aftermarket rod bolts is recommended. At this point in time, there are plenty of aftermarket forged rods from which to choose, to provide even greater durability than the OE PM rods. The OE rod bolt is 9mm, but Katech offers a 10mm rod bolt to work with OE rods.

According to Newman at Katech, the LS6 will safely over-bore to the same diameter as the LS1, but the LS6 features a sturdier engine case and is a better choice for overboring than the LS1. Newman noted that the larger-displacement LS2 is a less-expensive and superior block than either the LS1 or LS6, and offers much more interchangeability with LS6 OE production parts. Confusing, isn’t it? Welcome to the LS.

How large a displacement can you easily obtain by increasing bore diameter and stroke?

According to Katech’s Newman, the LS1 or LS6 (originally 345 CID) can be sized to a max of 414 CID using a 4.000″ stroke. The LS2 (originally 364 CID) can be easily oversized to 427 CID max as well. Newman noted that 414 CID is the biggest you can go with a dry sleeve on the LS1/LS6. The LS2 can go to 427 CID with a dry sleeve.

Modifications intended to achieve greater strength and durability include changing to forged crankshafts, connecting rods and pistons, billet main caps, replacement connecting rod bolts, the use of head and main studs and oil pump modification, among other tricks. Oil pump mods include disassembly, deburring the pump inside and out, porting the oil entrance, polishing the pressure relief section and reassembly.

Editor’s Note: The majority of the information presented here was graciously provided to us by Katech Performance. Katech has been around for over 30 years and has built a vast array of championship-winning race engines. Katech has also been closely involved with GM during the development of the LS series of engines, and has developed an extremely wide range of performance engine components for this engine series.

I would like to extend our sincere appreciation to both Caleb Newman and Jason Harding at Katech Engine Development for their courtesy, time and expertise in helping to prepare this information for our readers.

UPCOMING PROJECT

Now that we’ve provided an overview of the LS engine family, it’s time to get our hands dirty once again. We’ll soon begin to build a special LS project engine during 2008 and rest assured that we’ll supply all of the details as we go, with a dyno run at the completion of the build.

chart5

chart6

LS ENGINE TECH (Part 1)

LS ENGINE TECH

The current new ­generations of GM ­engines are here to stay and ­represent the hot ticket for today’s and ­tomorrow’s ­hot-dog smallblocks for both street ­performance and racing applications. It’s time to get up to speed.

by Mike Mavrigian

photos by author

01

LS6 aluminum 5.7L block.

02

LS2 aluminum 6.0L block.

The Gen III and Gen IV (Gen IV is the most current) family of GM smallblock engines. With the LS1 debuted in 1997, the LS, or Gen III, has been in consumers’ hands now for over 10 years and is beginning to gain momentum in the performance aftermarket. It’s painfully obvious that it’s high time we started taking an in-depth look at the new smallblock, which is predicted to be as popular as the original Gen I Chevy smallblock that began production back in 1955.
The Gen III engine started from scratch, a clean sheet of paper in terms of design. Aside from cylinder bore spacing, rod journal diameter and lifter diameter, the Gen III has nothing in common with previous smallblocks.

The entire Gen III family of engines includes more than 5.7 and 6.0L versions. Included are the 4.8L LR4, the 5.3L LM4, 5.7L LS1 and LS6, 6.0L LQ4 and 6.0L LQ9.

Truck and SUV Gen III engines featured iron blocks with iron heads and, in some applications, iron blocks with aluminum heads. The Escalade is the only SUV application that used an aluminum block and aluminum heads.
In Corvette, Camaro, Firebird, GTO and Cadillac CTS-V applications, all LS1 and LS6 engines featured aluminum blocks with aluminum heads.

GEN III SIMILARITIES TO GEN I

4.400″ bore spacing
2.10″ rod journal diameter
Valve train oiling through the pushrods
0.842″ lifter diameter
Single-piece rear main seal (similar to late Gen I and Gen II)

GEN III DIFFERENCES

Here are the primary design changes that represent the basics of the Gen III engine:
Block deck height is 9.240″ (up from 9.025″)
Firing order is 1-8-7-2-6-5-4-3 (Gen I/II is 1-8-4-3-6-5-7-2)
Bank offset changed to 0.9488″ (from previous 0.8800″)
Y-skirt block
Cast aluminum sump
No distributor provision
Lighter weight (approx. 430 lbs. vs. Gen I 531 lbs.)
Connecting rod length is 6.098″ (vs. previous 5.700″)
On-center beam connecting rods (no offset)
Piston pin diameter 0.940″ (vs. previous 0.927″)
Crank thrust has moved from the rear to the No. 3 main bearing
Cam-to-crank centerline distance is 4.914″ (vs. previous 4.521″)
The crankshaft flange has moved 0.40″ closer to the rear of the block
Water temperature is controlled on the intake side of the water pump
Replicated ports vs. mirrored ports

HEAD BOLTS

According to Katech’s Jason Harding, the LS1 and LS6 feature two different length hex-head cylinder head bolts (10mm x 100mm and 10mm x 155mm), later LS2, LS7, LS3 and L92 engines use only the 10mm x 100mm head bolt length.

Additional pinch bolts at the inboard edge of the cylinder head uses 8mm x 45mm hex head bolts. All LS heads require 10 primary cylinder head bolts, plus five 8mm pinch bolts. All primary head bolts are TTY (torque-to-yield) type and feature OEM thread locking compound. All head bolts enter blind holes, so none are open to water or oil.

BLOCK AND CRANK NOTES

All LS blocks feature a 4.400″ bore spacing and a bank angle of 45 degrees. The OE aluminum blocks are cast from 319 aluminum and feature vent holes (cast or drilled) in the main webs.

The LS series of blocks and cranks feature the thrust bearing located at the No. 3 main as compared to the rear-located early Chevy engines. Engine rotation is clockwise.

Note: While the Chevy service manuals may note that the damper bolt should not be re-used, this is not because the damper bolt is TTY, because it’s not. Rather, they recommend damper bolt replacement only because the underside of the bolt head features an OE friction-reducing contact surface that may be worn away on a damper bolt that has been installed and removed.

All LS series blocks feature individual main caps that are secured with a total of six bolts. This includes four primary (vertical) bolts plus two side bolts that enter through the outside of the block, above the pan rail. Because of this side-bolt design, which offers superior rigidity, main caps cannot be ground to reduce the bore size if align-boring is needed, as this would throw the side bolts out of register. If the main bores must be machined in order to correct a roundness or center issue, oversize-O.D. main bearings would then be required. The LS7 is the only version that came OE with billet main caps. All other LS main caps are PM steel. However, Caleb Newman with Katech noted that small changes can still be made to the caps without throwing them away, as a small bit of clearance exists at the side holes.

LS series engines utilize a front-mounted keyed, crank-driven oil pump.
All LS cranks are cast, again with the exception of the LS7 cranks, which are forged.

The LS1 and LS6 blocks, though sharing the same dimensions, differ somewhat, with the LS6 block featuring slight changes in main web design for crossover breathing (the LS6 block main webs are slightly skeletonized).

Crankshaft counterweights are cam-ground to clear piston skirts. Cam grinding also makes crank balancing a bit easier.

Newman noted that Katech developed a proprietary process for sleeving up to a 4.125″ bore on the LS2. If stock bores are desired, it’s more cost effective to buy a new block. If sleeving is required for an aluminum block, all eight cylinders are bored to size, then honed to size for each individual liner. The new liners are installed at 270 degrees F and are then torqued three times during the cooling process. Liner bottoms must also be notched for rod clearance. The block is then decked, the main caps are installed, and the main bore is bored or honed. The block is then double-vacuum impregnated. The liners are then bored and honed for individual piston fit.

Katech notes that a GM performance Parts Race Case is available that features 356 aluminum, Siamesed bores, steel billet main caps and 7/16″ main and head bolt locations. This block will accept 4.125″ bores.

chart1

chart2

chart31

chart4

PROJECT 632 PART 6:DELIVERANCE (6G)

55

The vacuum pump and alternator setup hangs low, leaving the head area clean.

56

Belt tension adjustment on radius tooth setups don’t require much tension at all, which removes a bit of stress from the crank. The tooth engagement alone provides a positive pulley drive.

57

Routing the -12 plumbing from the vacuum pump to the valve covers allowed a simple path for the hoses that doesn’t obstruct anything.

58

A Jegs billet aluminum water neck housing features a 24-pound Moroso cap and three available threaded ports on the backside for attaching extra water lines and/or a temperature sensor.

59

Yes, I checked rocker arm clearance at the valve covers. No problem. The Moroso welded aluminum covers are very light and sleek.

61

Why is this guy smiling? Hey, the assembly is done and it’s been a long time coming. Maybe I can sneak in a day or two for some fly fishing.

60

As usual, I performed the entire build on a Goodson engine cart. With a roll-around design, an upper drip/work tray and lower storage tray; these carts are my favorites.

62

Our engine at Gressman Powersports during dyno mounting.

63

Gressman’s Superflow dyno features a cooling tower through which our cooling system was managed.

64

Gressman’s exhaust headers are fitted with thermocouplers to monitor exhaust gas temperature at individual cylinders.

65

Following the first test-run at low RPM, Scott Gressman makes a minor fuel mixture adjustment. Our Holley Dominator performed superbly, virtually out of the box. We made no jet changes at all during our brief dyno session.

66

The BG fuel rail performed perfectly, with no leaks. The three O-rings in the sliding tube system do indeed provide proper sealing. We adjusted the Race Pumps fuel pressure regulator to settle at about 9 pounds pressure.

67

After test running and full warm-up, Gressman re-checks valve lash, setting intakes and exhausts at 0.028 inches.

69
Gressman ran the dyno board. Here he makes a few last-minute system checks. Our first pull yanked 1,098 horsepower, not bad for an out-of-the-box run. Our best pull netted 1,115 horsepower.

68

Following a couple of test runs to perform our pre-flight checks, the air feed stack is installed and we’re ready to make our first hard pull.

 

THE DYNO RUN

For better or worse, the moment of truth was finally upon us. In the later afternoon of September 19, I transported the engine to Gressman Powersports in Fremont, Ohio (only about 90 miles from my shop).  Scott Gressman maintains a SuperFlow engine dynomometer. On the way to Gressman’s shop, I stopped at a race fuel distributor and picked up 10 gallons of VO 114-octane leaded race fuel (at a whopping $13.86 per gallon!).

The next day, Gressman’s crew mounted the engine to the dyno stand and connected the fuel and cooling plumbing, wired the Meziere electric water pump, installed their thermocoupler-equipped exhaust headers, etc. Prep took about one hour.

After adding 7 qts of 30-weight oil to the sump, the distributor was removed and the oil pump drive shaft was rotated with a cordless drill to pump oil through the engine for priming. Initial timing was set at 25 degrees. All timing adjustments were made at the MSD crank trigger sensor (by moving the sensor in relation to the trigger wheel).

With everything in place, Scott hit the starter and much to my relief, she fired and ran (I’m always antsy whenever a fresh motor first comes alive). Scott allowed her to run for a few minutes at around 1,400 – 1,500 RPM while monitoring the vitals. We immediately had about 65 lbs of oil pressure (which bumped to 80 psi during pulls), and no leaks occurred anywhere on the motor.

After allowing the engine to warm up, Scott shut her down and re-checked hot valve lash, setting all valves at 0.028”.

The first hard pull, with timing set at 27 degrees, with a pull netting 1,098 HP at 7,150 RPM. A second pull, with timing at 30 degrees, yanked 1,105 HP at 7,150 RPM. The final pull, at 32 degrees timing, and with the camshaft retarded 3 degrees, produced 1,115 HP at 7,150 RPM.

Torque wasn’t as high as we had expected, to be honest. The best we pulled (on the first run) was 882.0 lb-ft. On our best horsepower pull, the highest torque reading was 863.4 lb-ft. We had expected torque to be in the mid-to-high 900 range. But again, these are still respectable numbers, and with further tweaking, we feel very confident that there’s more to be had.

 

 

OUR FINAL DYNO PULL

 

RPM           TORQUE            HP

5200                                                 844.4                                             836.0

5300                                                 846.8                                             854.5

5400                                                 851.9                                              875.9

5500                                                 855.8                                              896.2

5600                                                 860.5                                              917.5

5700                                                 863.9                                              937.6

5800                                                864.2                                             954.4

5900                                                  863.3                                              969.8

6000                                                  862.5                                              985.4

6100                                                   863.7                                            1003.1

6200                                                   860.1                                            1015.4

6300                                                   858.5                                            1029.8

6400                                                   855.5                                            1042.4

6500                                                   854.0                                            1056.9

6600                                                   850.5                                            1068.8

6700                                                   848.0                                            1081.8

6800                                                   842.5                                             1090.8

6900                                                   835.9                                              1098.1

7000                                                   829.5                                              1107.6

7100                                                   823.0                                               1115.5

7200                                                   811.4                                                1112.3

7300                                                   798.1                                                1109.3

 

In the 5700 – 6200 RPM range, average Fuel A lb/hr was 174.5. Fuel B lb/hr was 170.9. A/F ratio was 14.79 (max 15.31). Average volumetric efficiency was 113.6%.

 

 

Scott felt comfortable that with more timing tweaks, and perhaps switching to dual 1050 carbs, we would likely hit somewhere between 1,150 to 1,200 HP. Unfortunately, we had only a limited timeframe to use the dyno, but for an initial out-of-the-box run, 1,115 HP isn’t bad at all. I was surprised at how incredibly responsive the engine was. She snapped revs quicker than a hungry dog chowing-down a bowl of Kibbles. And the horrific shriek she made at high revs was both scary and wonderful. She’s definitely a nasty lil’ rat.

 

I have no illusions that we’ve created the best of anything. I know full well that many of our readers could pull bigger horsepower and torque with various tweaks to cam profile, ignition timing and fuel delivery. But, what we’ve accomplished in this build series definitely lays the groundwork for this type of build. We hope you’ve enjoyed the project and above all, we hope that the information we’ve provided is of some benefit. I think that the information (in terms of component selection and prep) provides a very good guideline for a similar build that you may have in mind, or one that is requested by a customer.

 

 

 

 

PRODUCT SUPPORT

Thanks to the following for their involvement in this project…

 

 

ARP INC.

1863 Eastman Ave.

Ventura, CA 93003

805-339-2200

www.arp-bolts.com

 

 

ATI PERFORMANCE PRODUCTS

6747 Whitestone Rd.

Baltimore, MD 21207

410-298-4343; 800-284-3433

www.atiracing.com

 

 

BG FUEL SYSTEMS

1450 McDonald Rd.

Dahlonega, GA 30533

706-864-8544

www.barrygrant.com

 

 

 

CAM LOGIC

(Bolton Conductive Systems)

1164 Ladd Rd.

Walled lake, MI 48390

248-669-7080

www.camlogicsystem.com

 

 

CAM MOTION, INC.

2092 Dallas Dr.

Baton Rouge, LA 70806

225-926-6110

www.cammotion.com

 

 

 

CLEVITE ENGINE PARTS

1350 Eisenhower Place

Ann Arbor, MI 48108-3282

734-975-7938

www.engineparts.com

 

 

 

CRANE CAMS, INC.

530 Fentress Blvd.

Daytona Beach, FL 32114-1200

386-252-1151

www.cranecams.com

 

 

 

DART MACHINERY

353 Oliver St.

Troy, MI 48084

248-362-1188

www.dartheads.com

 

 

 

DIAMOND RACING PRODUCTS

23003 Diamond Dr.

Clinton Twp, MI 48035

586-792-6620

www.diamondracing.net

 

 

FALL AUTOMOTIVE MACHINE

3519 Jackman Rd.

Toledo, OH 43612

419-473-1557

 

 

GEAR HEAD TOOLS

P.O. Box 21887

Carson City, NV 89721-1887

877-245-0014

www.HearHeadTools.com

 

 

GOODSON TOOLS & SUPPLIES

156 Galewski Dr.

Winona, MN 55987

800-533-8010

www.goodson.com

 

 

GRESSMAN POWERSPORTS

904 Lime St.

Fremont, OH 43420

419-355-8980

www.gressmanpowersports.com

 

 

HOLLEY PERFORMANCE PRODUCTS

1801 Russellville Rd.

Bowling Green, KY 42101

270-782-2900

www.holley.com

 

 

 

JESEL VALVETRAIN INC.

1985 Cedarbridge Ave.

Lakewood, NJ 08701

732-901-1800

www.jesel.com

 

 

 

JONES RACING PRODUCTS

72 Annawanda Rd.

Ottsville, PA 18942

610-847-2028

www.jonesracingproducts.com

 

 

 

 

LUNATI

(see Holley Performance Products)

 

 

MANTON RACING PRODUCTS

558 Birch St., Bldg 4

lake Elsinore, CA 92530

951-245-6565

www.mantonpushrods.com

 

 

MEZIERE ENTERPRISES INC.

220 S. Hale Ave.

Escondido, CA 92029-1719

760-746-3273; 800-208-1755

www.meziere.com

 

 

 

MOROSO PERFORMANCE PRODUCTS

80 Carter Dr.

Guilford, CT 06437

203-453-6571

www.moroso.com

 

 

MSD IGNITION

1490 Henry Brennan Dr.

El Paso, TX 79936-6805

915-857-5200

www.msdignition.com

 

 

PRO-FILER PERFORMANCE PRODUCTS

P.O. Box 217

New Carlisle, OH 45344

937-846-1333

www.profilerperformance.com

 

 

RACE PUMPS

222 Hillcrest Dr.

High Point, NC 27262

336-476-9583

www.racepumps.com

 

 

 

ROYAL PURPLE, LTD.

One Royal Purple Lane

Porter, TX 77365

888-382-6300

www.royalpurple.com

 

 

SUNNEN PRODUCTS CO.

7910 Manchester Ave.

St. Louis, MO 63143-2793

800-772-2878; 314-781-2100

www.sunnen.com

 

 

TRICK FLOW SPECIALTIES

285 WEST AVE.

TALLMADGE, OH 44278

330-630-5560

www.trickflow.com

PROJECT 632 PART 6:DELIVERANCE (6F)

42

Even though the drive hub system will be clamped to the crank snout with the 6-inch long center bolt to prevent the possibility of independent hub rotation, two roll pins are installed to the hub. The countersunk inside face of the ATI Super Damper was then drilled to accept these roll pins.

43

Plumbing the vacuum pump is very straightforward. The two -12 vacuum inlet ports (seen here) are plumbed to the valve covers. A single -12 exhaust port (located on the opposite side of the pump body) is plumbed to a remote breather.

44

Although the prospect of a stainless-steel braided hose collapsing under vacuum may seem remote, Jones Racing suggests the installation of a flat-wound support coil to eliminate this concern.

45

In order to connect the vacuum pump plumbing to the valve covers, I had a -12 male AN fitting Tig welded to the front face of each valve cover.

46

I always use dedicated aluminum AN wrenches for any aluminum AN connection. This greatly minimizes the chance of burring the aluminum hose end assembly or marring the anodized finish.

47

The vacuum pump pulley is mounted to a shaft that registers on a long keyway groove, allowing you to adjust the fore/aft pulley position for perfect alignment to the drive pulley. Three set screws lock the pump pulley in place, and Jones Racing provides access holes in the pulley for these set screws.

48

Since we’re using a vacuum pump, the engine must be sealed (so I couldn’t install a breather on a valve cover). In order to provide an oil-fill port, we welded a bung to the roof of the left side valve cover. A Jones Racing threaded cap (O-ring sealed) plugs the hole.

49

In order to provide radiator hose clearance for the water pump, Jones Racing supplied an extension bracket. This mounts to the block, behind the crank trigger sensor bracket.

50

The drive hub spacers on the mandrel allowed easy alignment for both alternator and vacuum pump pulleys.

511

90 degree-12 AN hose ends were used at both pump and valve cover locations.

52

Although function was more of a concern than appearance, the blue (hose end, valve cover knobs, oil fill plug and plug wire boot sleeves) helped to provide a bit of contrast against the aluminum background.

53
The 65-amp race alternator from Jones Racing is light and the mounting brackets were superb. Note the heim-joint adjuster. Jones told us that this is an intelligent alternator that won’t rob horsepower. Jones Racing also builds this alternator in-house.

54

The alternator bracket assembly fit perfectly, with no massaging required.

PROJECT 632 PART 6:DELIVERANCE (6E)

30

The BG fuel log is adjustable for length, allowing bowl-to-bowl spacing to be set by simply slipping the male tube inside the female tube.

31

The male tube section of the BG fuel log features three sealing O-rings.

32

Fitting the BG fuel rail to our Dominator was a piece of cake. I installed the Race Pumps fuel pressure regulator to the inlet of the fuel rail.

33

The BG fuel rail came with a pair of carb standoff extensions that allowed the fuel rail to clear the carb perfectly.

34

During fuel line plumbing, I used all –8 AN hose, hose ends and adapters. I installed a Trick Flow billet aluminum 40-micron fuel filter at the inlet of the regulator.

35

Although some drag racers use air filters and some don’t, I thought it wise to protect our baby. This K&N X-Stream filter measures 14 inches in diameter and five inches in height, with a pleated lid, so our big-daddy carb can suck from the perimeter and from the top. Other size combinations are also available.

36

The K&N filter kit included a base adapter and stud kit. I used another Cam Motion Top Seal knob to secure the K&N filter top.

37

Our Jones Racing two-stage vacuum pump will provide a consistent 15 inches of vacuum (negative pressure) inside our mill.

38

The vacuum pump mounting bracket features an adjustable slot for easy belt service and tension adjustment.

39

The vacuum pump features a radius-tooth pulley with aluminum belt guides.

40

The drive hub assembly from Jones Racing allows mounting the drive pulleys for our alternator and vacuum pump.

41

The drive hub arrangement features a number of aluminum spacer rings, that can be swapped around to achieve desired pulley location.

PROJECT 632 PART 6:DELIVERANCE (6D)

04

Our initial distributor offered a very neat low profile, but the large diameter of the head made installation impossible due to a lack of intake plenum clearance, so I switched out to a smaller-diameter-head MSD.

05

The MSD Pro-Billet distributor (P/N 85501) provided the intake manifold plenum clearance that we needed.

07

Our MSD distributor features a slip collar, allowing installed height adjustability.

08

In order to fit the Dart block, the nose of the drive gear was shortened and reduced in diameter (see the machined section that contrasts here with the machinist blue dye).

09

During distributor-height adjustment, I made sure that the distributor shaft’s oil groove lined up with the block’s oil passage.

10

The final distributor height brought the underhead chamfer a bit close to the slip collar, so I ground the top of the hold-down clamp for proper fit.

11

Our MSD 8.5mm Super Conductor spark plug wire kit.

12

I went a bit overboard with plug wire clamps in an effort to nail all of the wires down to prevent them from flopping around. I made two L-brackets that attach to the rear manifold bolts to provide a mounting spot for the four-wire MSD wire dividers.

13

The MSD wire dividers feature a snap-on/off cap for easy wire servicing. The divider base is secured to the custom L-brackets via an 8 x 32 stainless-steel button head screw and nyloc nut.

14

DEI’s spark plug boot protector sleeves are offered in a variety of colors, but I chose blue for this build.

15

The DEI sleeves feature a heat-resistant Kevlar weave.

16

The smaller-diameter rolled end snugs over the spark plug boot.

17

The rolled end of the heat shield sleeve features an internal metal ring that snugs the sleeve onto the boot. This prevents the sleeve from walking off of the boot and eliminates the need to secure the sleeves with zip ties.

18

I routed the plug wires under the exhaust ports. The sleeves protect the boots from heat and protect the wires from abrasion as well.

19

Our valve covers are Moroso’s welded aluminum big block units.

20

The standard method of securing the valve covers involves the use of 1/4-inch x 20 socket head cap screws (provided with the covers). However, I decided to install 1/4-inch x 20 x 4-inch studs in the heads, allowing me to use knurled aluminum knobs for clamping.

21

The knobs (from Cam Motion) are designed for use with air cleaners, but I thought that they’d be practical for valve cover use since no tools are required. They may seem a bit large in diameter, but they’re super-easy to handle.

22

Cam Motion offers these Top Seal knobs in two different heights and in a variety of colors.

23

I didn’t need the height offered by the tall design, so I went with the short version for the sake of appearance and clearance (no need to have ‘em sticking up further for no reason).

24

The Cam Motion Top Seal knobs are equipped with O-rings, which provide grip and sealing when used to clamp air cleaner lids. For my use on the valve covers, I simply removed these O-rings.

26

The blue valve cover knobs may look a bit large, but they’re very user-friendly. Hey, they kinda match the blue spark plug boot sleeves too.

27

The Victor Reinz valve cover gaskets feature a stainless core sandwiched between the rubberized cork layers, making them nice and stable, so they won’t slip in/out of location.

28

We had a choice of upper plenum boxes for our Profiler intake manifold, allowing us to use either one carb or two. For this build, I opted for a single Holley 1,150 cfm Dominator.

29

The Dominator carb, with its 1,150 cfm volume, should provide adequate air/fuel for our nutty cam and Big Chief II heads.

PROJECT 632 PART 6:DELIVERANCE (6C)

jones-racing-chart1

CARBURETOR/FUEL PLUMBING

Our big-gulp carb is Holley’s Ultra Dominator (P/N 0-80673), an 1,150 cfm race carb that features billet metering blocks, three-circuit metering, mechanical secondaries and oversized sight windows for easy float adjustment. Recommended fuel pressure is 5-7.5 psi. The anodized billet metering blocks feature changeable idle feed restrictors for easier tuning of the idle system with no drilling, in addition to changeable emulsion jets for infinite metering tuning.

In order to handle fuel feed to our mega-displacement carb, I installed a BG P/N 170021 adjustable-length fuel log (adjustable for bowl inlet match-up), a pair of BG fuel inlet extension fittings P/N 140023 (7/8 x 20 x -8 swivel), a Trick Flow -8 TFS-23001 inline billet fuel filter, a BG fuel pressure gauge (P/N 170124) and RacePump’s fuel pressure regulator (P/N 5010).

The BG adjustable fuel log is pretty cool. In order to adjust length, simply slide the two ends apart or closer together by hand. One tube slides inside the mating tube, internally sealed with a series of three special O-rings, so no tools are required to adjust the log tube length. Either end may be used for the fuel inlet (each end features a 3/8-inch NPT female thread), and one end features two 1/8-inch NPT ports to allow mounting a fuel pressure gauge on either side (depending on how you orient the log). Install the two extension fittings to the carb, adjust the log length to align to the fittings and install, tightening evenly (back and forth between the two fittings to prevent binding).

The BG pressure gauge is also very neat. It’s internally dampened without the use of liquid (since a liquid-filled gauge might be affected by engine heat and lead to
inaccurate readings). I plumbed everything using Earl’s -8
stainless braided hose. At the fuel pump outlet, I used a 45-degree -8 hose end. At each side of the filter, I used -8 straight hose ends. At the entry of the fuel pressure regulator, I used a -8 straight hose end attached to a -8 male to 1/2-inch NPT male adapter (the bottom inlet port of the regulator features a 1/2-inch NPT thread).

AIR FILTER

Although not needed for the dyno run itself, I opted for a way-cool K&N X-Stream air cleaner assembly, (P/N 66-3090). This assembly features a 14-inch x 5-inch-high round open-element filter in addition to an open-element top. The kit included all mounting hardware, including a neoprene base gasket for the Dominator, a chrome steel base, a 5/16-inch x 18 male to 1/4-inch x 20 female adapter, a length of 1/4-inch x 20 all-thread, two steel washers, one rubber washer and 1/4-inch x 20 nuts. The only fiddling involves cutting the all-thread to length to accommodate the filter height. Install the 5/16-inch to 14-inch adapter to the carb and install a 1/4-inch x 20 jam nut on the all-thread (against the adapter top). Install a 1/4-inch x 20 nyloc locknut onto the all-thread. Install the base gasket, the steel baseplate and the round filter.

Lay a straightedge across the top of the round filter element, and position the top of the nyloc nut three turns below the bottom of the straightedge. Next, remove the all-thread (keep the nyloc nut in place). Mark the all-thread at a point 1.250 inches above the top of the nyloc nut and cut off the excess all-thread at this mark (you want 1.250 inches of thread exposed above the nyloc nut). Deburr and chamfer the cut all-thread. Reinstall the all-thread stud. Place one steel washer on the all-thread, resting the washer onto the top of the nyloc nut. Install the top filter element, making sure that it’s seated into the steel baseplate. Install the rubber washer onto the exposed stud, followed by a steel washer and a 1/4-inch x 20 nut.

K&N supplies a nyloc nut for the top of the stud, but I opted for a burgundy-anodized Top Seal billet aluminum knurled air cleaner lid knob (1/4-inch x 20 internal thread) that I obtained from Cam Motion. These knobs (available in short and tall versions) look way cool and provide convenient hand operation for air filter servicing. An O-ring is featured on the underside (seated in a milled groove) to prevent slippage and unwanted loosening.

THERMOSTAT HOUSING

I installed a blue anodized aluminum thermostat housing/intake filler assembly from Jeg’s (P/N 53012). This features a 1.5-inch diameter radiator hose connection. The two-piece design allows you to flip the lower housing to orient the hose nipple to either the right or left side of the engine. The lower housing seals to the manifold via our Victor race gasket (aluminum core with silicone seals). The upper neck seals to the main housing with a built-in O-ring seal. An overflow nipple screws into the neck via a 1/8-inch NPT thread. The rear of the main housing features two 1/4-inch NPT and one 3/8-inch NPT female ports, which I sealed off with NPT plugs (these could be used for additional coolant plumbing, gauge or sensor attachment, etc.).

For a pressure cap, I chose Moroso’s 24-pound race cap (P/N SDC-63324).

THE DYNO RUN

For better or worse, the moment of truth was finally upon us. In the later afternoon of September 19, I transported the engine to Gressman Powersports in Fremont, Ohio, (only about 90 miles from my shop). Gressman maintains a SuperFlow engine dynomometer. On the way to Gressman’s shop, I stopped at a race fuel distributor and picked up 10 gallons of VP 114-octane leaded race fuel (at a whopping $13.86 per gallon!).

The next day, Gressman’s crew mounted the engine to the dyno stand and connected the fuel and cooling plumbing, wired the Meziere electric water pump, installed their thermocoupler-equipped exhaust headers, etc. Prep took about one hour.

After adding seven quarts of 30-weight oil to the sump, the distributor was removed and the oil pump drive shaft was rotated with a cordless drill to pump oil through the engine for priming. Initial timing was set at 25 degrees. All timing adjustments were made at the MSD crank trigger sensor by moving the sensor in relation to the trigger wheel.

With everything in place, Gressman hit the starter and much to my relief, she fired and ran (I’m always antsy whenever a fresh motor first comes alive). Gressman allowed her to run for a few minutes at around 1,400-1,500 RPM while monitoring the vitals. We immediately had about 65 pounds of oil pressure (which bumped to 80 psi during pulls), and no leaks occurred anywhere on the motor.
After allowing the engine to warm up, Gressman shut her down and re-checked hot valve lash, setting all valves at 0.028 inches.

The first hard pull, with timing set at 27 degrees, netting 1,098 horsepower at 7,150 RPM. A second pull, with timing at 30 degrees, yanked 1,105 horsepower at 7,150 RPM. The final pull, at 32 degrees timing and, with the camshaft retarded 3 degrees, produced 1,115 horsepower at 7,150 RPM.

Torque wasn’t as high as we had expected, to be honest. The best we pulled (on the first run) was 882.0 lbs./ft. On our best horsepower pull, the highest torque reading was 863.4 lbs./ft. We had expected torque to be in the mid-to-high 900 range. But again, these are still respectable numbers, and with further tweaking, we feel very confident that there’s more to be had.

OUR FINAL DYNO PULL

RPM……….TORQUE……….HP

5,200……….844.4……….836.0
5,300……….846.8……….854.5
5,400……….851.9……….875.9
5,500……….855.8……….896.2
5,600……….860.5……….917.5
5,700……….863.9……….937.6
5,800……….864.2……….954.4
5,900……….863.3……….969.8
6,000……….862.5……….985.4
6,100……….863.7……….1,003.1
6,200……….860.1……….1,015.4
6,300……….858.5……….1,029.8
6,400……….855.5……….1,042.4
6,500……….854.0……….1,056.9
6,600……….850.5……….1,068.8
6,700……….848.0……….1,081.8
6,800……….842.5……….1,090.8
6,900……….835.9……….1,098.1
7,000……….829.5……….1,107.6
7,100……….823.0……….1,115.5
7,200……….811.4……….1,112.3
7,300……….798.1……….1,109.3

In the 5,700-6,200 RPM range, average Fuel A lbs./hr. was 174.5. Fuel B lbs./hr. was 170.9. A/F ratio was 14.79 (max 15.31). Average volumetric efficiency was 113.6 percent.

Gressman felt comfortable that with more timing tweaks, and perhaps switching to dual 1050 carbs, we would likely hit somewhere between 1,150 to 1,200 horsepower. Unfortunately, we had only a limited timeframe to use the dyno, but for an initial out-of-the-box run, 1,115 horsepower isn’t bad at all. I was surprised at how incredibly responsive the engine was. She snapped revs quicker than a hungry dog chowing down a bowl of kibbles. And the horrific shriek she made at high revs was both scary and wonderful. She’s definitely a nasty lil’ rat.

I have no illusions that we’ve created the best of anything. I know full well that many of our readers could pull bigger horsepower and torque with various tweaks to cam profile, ignition timing and fuel delivery. But, what we’ve accomplished in this build series definitely lays the groundwork for this type of build. We hope you’ve enjoyed the project and, above all, we hope that the information we’ve provided is of some benefit. I think that the information (in terms of component selection and prep) provides a very good guideline for a similar build that you may have in mind, or for one that is requested by a customer.

Source Box

ARP Inc.
For more information,
Dial 1-800-652-0406, ext. 17401

ATI Performance Products
For more information,
Dial 1-800-652-0406, ext. 17402

BG Fuel Systems
For more information,
Dial 1-800-652-0406, ext. 17403

Cam Logic (Bolton Conductive Systems)
For more information,
Dial 1-800-652-0406, ext. 17404

Cam Motion Inc.
For more information,
Dial 1-800-652-0406, ext. 17405

Clevite Engine Parts
For more information,
Dial 1-800-652-0406, ext. 17406

Crane Cams Inc.
For more information,
Dial 1-800-652-0406, ext. 17407

Dart Machinery
For more information,
Dial 1-800-652-0406, ext. 17408

Diamond Racing Products
For more information,
Dial 1-800-652-0406, ext. 17409

Fall Automotive Machine
For more information,
Dial 1-800-652-0406, ext. 17410

Gear Head Tools
For more information,
Dial 1-800-652-0406, ext. 17411

Goodson Tools & Supplies
For more information,
Dial 1-800-652-0406, ext. 17412

Gressman Powersports
For more information,
Dial 1-800-652-0406, ext. 17413
Holley Performance Products/Lunati
For more information,
Dial 1-800-652-0406, ext. 17414

Jesel Valvetrain Inc.
For more information,
Dial 1-800-652-0406, ext. 17415

Jones Racing Products
For more information,
Dial 1-800-652-0406, ext. 17416

Manton Racing Products
For more information,
Dial 1-800-652-0406, ext. 17417

Meziere Enterprises Inc.
For more information,
Dial 1-800-652-0406, ext. 17418

Moroso Performance Products
For more information,
Dial 1-800-652-0406, ext. 17419

MSD Ignition
For more information,
Dial 1-800-652-0406, ext. 17420

Pro-Filer Performance Products
For more information,
Dial 1-800-652-0406, ext. 17421

Race Pumps
For more information,
Dial 1-800-652-0406, ext. 17422

Royal Purple LTD.
For more information,
Dial 1-800-652-0406, ext. 17423

Sunnen Products Co.
For more information,
Dial 1-800-652-0406, ext. 17424

Trick Flow Specialties
For more information,
Dial 1-800-652-0406, ext. 17425

PROJECT 632 PART 6:DELIVERANCE (6B)

VALVE COVERS

The 1/4-inch x 20 x 3.5-inch socket head cap screws supplied with the Moroso valve covers are fine, and function perfectly. But, being the anal dolt that I am, I wanted to dress things up a bit more. I installed stainless-steel 1/4-inch x 20 x 4-inch studs into the heads (purchased from McMaster-Carr under P/N 95412A558), and then secured the valve covers with Cam Motion’s Top Seal blue anodized billet aluminum knurled hand knobs. I selected their short-hat version at 0.637 inches tall (they also offer tall-top models at 1.136 inches high). All of their knobs feature a 1.50-inch diameter knurled hand-knob. The knobs are offered with either 1/4-inch x 20 or 5/16-inch x 18 female threads.

Granted, these knobs are intended for air cleaner lid use and may appear a bit large in diameter for valve cover use, but they’re extremely functional, adding a bit of convenience for hand-servicing the valve covers. Although this setup may be totally unnecessary, I thought it looked cool and the quick no-tool servicing would definitely come in handy in the pits.

In order to provide an oil-fill location, I installed a Jones Racing weld-in -12 female bung to the roof of the left side valve cover to serve as an oil fill port. This is sealed with a Jones Racing screw-in aluminum plug that features an O.D. hex and a sealing O-ring. Since we’re using the Jones Racing vacuum pump system, the engine needs to be sealed, so a valve cover breather was a no-no. Installing the bung required cutting a 1 5/8-inch hole in the cover (8 7/8 inches from the front wall, inline with the second pair of valve cover bolt locations, in an area where I knew I’d have a clear shot for oil fill between rocker arm locations).

In addition, a -12 weld-in male fitting was needed on the front wall of each valve cover in order to plumb to the Jones Racing vacuum pump. For each valve cover, a 3/4-inch hole was drilled and the male weld-on fitting was surface-mounted to the valve cover wall and Tig welded around the perimeter of the fitting’s hex.
Saeco, a local fab shop in nearby Wadsworth, Ohio, performed the Tig
welding of all three fittings (since yours truly doesn’t own a Tig, and doesn’t know how to use it even if he had one).

VACUUM PUMP

Jones Racing supplied a vacuum pump system featuring its lightweight billet aluminum vacuum pump VP-9100C. This is a two-stage gear-style vacuum pump that runs at 50 percent of engine speed and pulls a constant 15 psi, providing enhanced piston ring seal. The negative pressure created by the pump results in less resistance on the pistons during the compression downstroke, resulting in faster piston acceleration. This constant vacuum also helps to draw parasitic oil from the rotating assembly (theoretically increasing power) and allows the oil pump to function with less resistance, which should increase oil flow.

I mounted the pump on the lower right engine side. In order to provide clearance for the water pump neck, Jones supplied an extension bracket that shares the two block mounting bolts for the crank trigger sensor bracket.

In order to provide a mounting for the crank pulleys (for both our vacuum pump and our Jones Racing alternator), we installed Jones’ DH-8101-B BBC drive hub and their DHM-8101-B (3.500 inches x 1.125 inches O.D.) mandrel. The drive hub (and the hollow mandrel) secure to the crank snout with a 1/2-inch x 20 x 6-inch bolt. In addition, to prevent the drive hub from rotating independently, the hub
features two 3/16 inch roll pins. This required drilling a pair of 0.190-inch holes in the face of the damper (on the recessed flat face that surrounds the crank snout). The roll pins were pressed into the drive hub and the roll pins engage into the holes drilled in the damper.

The drive hub mandrel threads into the drive hub (featuring a left-hand thread) and features a 1/8-inch keyway slot that runs the entire length of the mandrel.
Once I mocked up the crank snout pulley and spacer assembly for proper pulley
alignment to both the alternator and vacuum pump pulleys, I removed the pulleys and spacers. I installed a 0.250-inch-thick spacer against the drive hub, then installed a key for the alternator drive pulley. The alternator drive pulley and its guide plates were slipped on, followed by three aluminum spacer rings (one 3/8-inch and two 1/2-inch thick spacers), followed by the vacuum pump drive pulley, one 1/2-inch spacer and finally the billet aluminum nose cup, loc washer and the 1/2-inch x 20 x 6-inch crank snout bolt. The array of aluminum spacers (in various thicknesses) allows you to tune the spacing of the pulleys on the mandrel.

In order to achieve fine-tuning of the vacuum pump’s pulley to the pump’s drive pulley on the crank mandrel, by loosening three set screws in the pump’s pulley, you’re able to slide the pulley fore/aft on the pump’s shaft for perfect belt alignment. Once alignment is determined, tighten the set screws. Access holes in the pump pulley allow easy entry for a hex wrench for servicing the set screws.
Routing the plumbing for the vacuum pump was super-simple. I made a pair of -12 hose assemblies using 90-degree -12 hose ends at each end of the two hoses.

The two outlet ports on the pump are plumbed directly to the -12 male weld-in fittings on the front face of each valve cover. The single outlet (exhaust) port from the pump will be plumbed to a remote breather in the dyno shop. Assembly of the -AN hoses was straightforward, in terms of installing the hose ends to the hoses (by the way, I used swivel-type hose ends at the valve cover locations to enable easy clock-position adjustment for a precise hose-end-to-fitting alignment).

The only special step involved inserting a section of Jones Racing’s flat-wound internal support coil into each hose length. This ensures the stability of the vacuum hose, preventing any potential restriction that might occur if the hose began to collapse internally under vacuum.

Initially, this was the pain in the butt part of the job. The stainless steel support coil must be wound counterclockwise to minimize its diameter (bringing the coils together, forming a tube), and then push-fed into the hose, pretty much one to three coils at a time. I lubed the inside of the hose with engine oil to ease insertion, but this was time consuming and frustrating in the beginning until I developed the knack.

I installed one hose end, installed the support coil, then installed the second hose end. The internal support coil comes in a 4-foot length. I cut two pieces with a snip, one for each hose. I tailored the coil length to match the full hose length between the hose ends (with the ends of the coil about 1/2-3/4 inches shy of each hose end). By the time I finished installing the support coils in the two vacuum hoses, I had resurrected just about every cuss word in my vocabulary. Of course, after fitting these two hoses, I felt like a pro.

ALTERNATOR SETUP

I mounted the Jones Racing alternator on the left side, using the existing threaded holes on the block face. The Jones mounting bracket fit like a friggin’ glove and it’s pretty to boot. Belt adjustment is a breeze, thanks to a heim-joint-ended LH/RH thread hex body turnbuckle. This is without a doubt the best-fitting and easiest-to-install custom alternator setup I’ve ever had the pleasure to install. Jones offers a multitude of alternator bracket configurations (for high-mount, low-mount, LH, RH, etc.), but I really like this little bugger. This is a nice application for both race engines and street rod builds, offering both form and function that would please even the most finicky customer. Very pro.

PROJECT 632 PART 6:DELIVERANCE (6A)

PROJECT 632 PART 6:DELIVERANCE

With assembly complete, it was time to light the candle.

by Mike Mavrigian

all photos by author

01

Well, the motor was final-assembled and run on the dyno. Although we didn’t hit our hoped-for 1,200 horsepower, we did manage a 1,115 horsepower run. With further tuning, we know the potential is there.
First, let’s cover the final stages of engine assembly, involving the
ignition system, fuel system and vacuum pump setup.

DISTRIBUTOR

You may recall from our last issue that I accidentally ordered the wrong distributor from MSD (P/N 8558, the Pro Billet low-profile distributor). There’s nothing wrong with the unit, but the large five-inch diameter head wouldn’t clear our tunnel ram plenum box. I recently obtained a replacement (MSD P/N 85501).

This is one of MSD’s Pro Billet units, featuring a lockout (no mechanical advance). It should work well with our crank trigger setup. Upon checking distributor fit, I found that the nose of the bronze distributor gear contacted the block (touching a boss inside the block at about the 1 o’clock position as you stare down into the distributor bore). Instead of stripping back down to a bare block to grind clearance, I followed Scott Gressman’s advice by applying machinist blue to the bronze gear assembly, inserting the distributor as fully as possible and rotating the crank one full revolution. Upon removing the distributor, I noticed a contact path around the perimeter of the gear nose (not the gear itself, but at the very bottom of the gear assembly nose). Since my lathe was down, Jody Holtrey at Medina Mountain Motors in Creston, Ohio (a mere stone’s throw from my office) removed about 0.070 inches from the bottom of the nose. In addition, he reduced the outer diameter of the nose by 0.020 inches, from the newly-cut bottom, up 0.250 inches. Finally, the bottom nose area was radiused into a bullet shape. With the right rear oil gallery plug removed from the block, I could view the distributor shaft’s oil band location relative to the block’s oil gallery, verifying that the distributor shaft’s oil band was in the oil path.

I carefully measured the distance from the top of the intake manifold distributor boss to the top of the oil pump intermediate shaft, which measured at 8.096 inches. Knowing that I wanted 0.200 to 0.250 inches of distributor-to-shaft engagement, I then knew that the distance from the bottom of the distributor gear’s key to the underside of the distributor’s slip collar should be approximately 8.346 inches. This provided me with a rough distributor depth target.

I was able to adjust the distributor depth via the distributor’s slip collar to achieve
distributor-to-intermediate shaft engagement of about 0.225 inches. With the distributor bottomed out, I then raised the distributor (using the slip collar adjustment) about 0.010 inches. I then rotated the crank two full revolutions, removed the distributor and inspected the bronze gear for evidence of a contact pattern relative to the cam’s gear. Once I was satisfied with shaft engagement and gear mesh, I final-tightened the distributor slip collar.

Once all height adjustment was complete, I cleaned the distributor shaft and gear and applied a coat of Royal Purple Max Tuff engine assembly lube to the shaft, gear and engagement key before final-installing the distributor.

The MSD distributor was supplied with a pair of rubber O-rings for the shaft. While some guys don’t bother with the O-rings, I followed Gressman’s advice by installing only the upper O-ring, the theory being that the absence of the lower O-ring allows a bit of oil to dribble down to the shaft during engine operation.

I used the MSD distributor hold-down bracket P/N 8110. Due to the set height of the distributor, I ran out of clearance for this beefy hold-down clamp. In order to fit the clamp between the top of the slip collar and the chamfered area of the distributor underhead, I ground the tops of both clamp arms down by about 0.030 inches.

PLUG WIRES

The MSD 8.5mm Super Conductor spark plug wires were then routed along the
bottom of the heads and cut to length. The distributor-end terminals and boots were installed, and the wires were connected to the distributor cap following the special firing order required by the Crane billet camshaft. Our firing order is 1-8-7-3-6-5-4-2 (big block Chevy order, with cylinders 4 and 7 swapped).

Our selected spark plugs are Autolite P/N AR3932 (0.750-inch reach plugs, per Dart’s recommendation for the Big Chief II heads). I set plug gap at 0.024 inches (they were all close to this gap straight out of the box).

In order to provide extra protection for the spark plug boots and wires from exhaust heat, I installed a set of DEI’s new Protect-A-Boots. These “cool” booties feature an internal metal ring at the small end, allowing you to nudge the boot small end over the plug boot ends for a snug fit that insures good retention of the thermal-guard boots. This is a nice feature, eliminating the need to secure the boots with tie straps.

In order to provide a degree of tidiness to the plug wires, I used MSD’s plug wire
spacers (P/N 8841) to serve as wire separators. In addition, to prevent the wires from flopping around at the rear of the block, I made two 90-degree aluminum brackets using 1-inch-wide x 0.125-inch-thick aluminum strap that secure to the two rear intake manifold bolts and extend down across the rear faces of the heads. These brackets provided an anchoring base for a pair of four-wire MSD Pro-Clamp wire separator blocks (from kit P/N 8843). I secured one four-wire block to each aluminum bracket with one 10 x 32 button head screw (I tapped a 10 x 32 hole in each bracket).

02

She’s a tall bugger for sure, measuring 42 inches from top to bottom.

03

The engine is now equipped with an external vacuum pump and race alternator.

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