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Sign up for our E-newsletterDart 11-Degree Big Chief Cylinder Head Specs
P/N………………………18500000
Material…………………355T6 aluminum alloy
Comb. Chambers……….56cc (70cc also available)
Intake valve dia…………2.470″
Intake port dim. …………1.815″ x 2.725″ w/3/4″ radius
Intake port volume………FP CNC – 497cc
Intake port location……..Raised 1.500″ spread ports
Exhaust valve dia………1.800″
Exhaust port volume……185cc
Exhaust port dim………..2.020″w x 1.780″h
Exhaust port location……angled & raised 0.900″ extended flange w/BBC bolt pattern
Intake flow………………520cfm @ 0.900″ lift/28″
SuperFlow 1020/+20cfm on SuperFlow 600
Exhaust flow…………….355cfm @ 0.900″ lift/28″
Lifter……………………..Use 0.180″ offset lifter
Manifold…………………Dart Big Chief Oval 1×4 bbl = 8″ tall
Milling…………………..56cc = 0.145″ (70cc = 0.080″)
Pistons…………………..Must use pistons for Big Chief head
Retainers………………..Titanium 10-deg
Spark plug………………0.750″ reach, gasketed Autolite AR3932
Spring cups……………..1.625″ – 0.060″ cup
Spring pockets………….1.740″ OD for 1.625″ cup (0.030″ deeper max)
Springs………………….Dart 1.625T = 330# @ 2.100″ / 0.910″ max Comp 948
Valve angles…………….Intake 11 deg x 6 deg Exhaust 7 deg x 4 deg
Valve length…………….Intake 6.600″ Exhaust 6.450″ (for 2.150″ installed height)
Valve stem dia…………..0.3415″ (11/32″) (5/16″ optional)
Valve train………………Jesel or T&D 11-deg rocker system
Valve guides…………….1/2″ OD Mag-bronze Cut for 0.500″ PC seals (0.002″ press)
Valve guide length………3.000″
Valve guide clearance……0.0014″ – 0.0021″ (with 0.3415″ dia. valve stem)
Valve guide spacing………widened for use on min. 4.600″ bore
Valve seats……………….Copper-Berylium, 0.008″ press
Valve seat dim. ………….Int 2.520″ x 2.00″ x 0.375″ Exh 2.000″ x 1.560″ x 0.375″
Valve seat angles……….. 55 deg
Head studs……………….ARP # 235-4312 (or Dart kit # 66120015)
Titanium valves………….Must use lash caps
Torque w/oil……………..Head bolts = 70 ft-lb
(Dart’s inner head studs 3/8″-7/16″ = 50 ft-lb
Manifold = 35 ft-lb
Block application………..Dart Big M, Mark IV, Gen V, Gen VI with proper head gasket
Cyl. Head weight………..42 lbs
The 0.5201 intake cam lift, when mated to our Jesel 1.85:1 rockers, will achieve an effective valve lift of about 0.962″. Lobe ramp angles are very shallow (to the eye, they look straight), so this pup should provide quite a rumpety-rump attitude.
Our roller lifters and valve springs were specially selected by Crane to suit our specific build.
This closeup shows the 0.180″ offset pushrod cup for the intake lifters, necessary for the Big Chief II 11-degree heads.
Our rocker system is a shaft roller setup from Jesel, featuring a hefty 1.85:1 ratio. Along with our custom Crane cam, this will provide nearly an inch of effective valve lift. Woof.
Our head gasket choice are MLS units from Victor.
Tri-Armor main and rod bearings from Clevite will create the necessary oil film to support our crank and rods. This is Clevite’s new line of coated bearings. The coating applied by Clevite is a proprietary polymer-based compound.
The Moroso billet gerotor style oil pump is a kick-ass unit with a built-in pickup screen, so there’s no worry about vibrating or cracking a pickup tube.
Here’s a closeup of the oil pump’s built-in pickup screen.
We opted for a Jesel belt drive for precision cam rotation.
We selected an 8″ ATI Super Damper to jive with our MSD flying magnet ignition system.
The Moroso wet sump aluminum oil pan is a recent addition to their line. The pan rail configuration requires extra tapped holes in the block’s rails.
Threaded plugs in the pan allow driver access to the center rail fasteners.
Moroso sheet metal aluminum valve covers will adorn the Dart Big Chief II heads.
The MSD Pro Billet distributor features a length that will accommodate the Dart tall-deck block.
The MSD flying magnet crank trigger will provide accurate ignition timing (this requires the use of an 8″ damper).
MSD Super Conductor plug wires are 8.5mm thick for carrying ample juice to this radical pup.
In order to take advantage of maximum coolant flow, and to eliminate the need for a water pump belt, we chose an electric pump from Meziere. This unit features a chrome finish, but black (and other colors) is also available.
Our giant-gulp carb is Holley’s 1150 cfm Dominator. This will be used if we opt for a single-carb intake manifold.
Depending on our intake manifold choice, we may run a pair of 1050s.
ARP threaded fasteners will be used throughout to anchor everything together. We opted for head studs instead of bolts.
Product Support
Thanks to the following for their involvement in this project…
Dial 1-800-652-0406 and then the Quik-Link number after a company to reach them directly!
www.precisionenginemag.com
ARP INC.
1863 Eastman Ave.
Ventura, CA 93003
Quik-Link #11064
ATI PERFORMANCE
PRODUCTS
6747 Whitestone Rd.
Baltimore, MD 21207
Quik-Link #11065
CLEVITE ENGINE PARTS
1350 Eisenhower Place
Ann Arbor, MI 48108-3282
Quik-Link #11066
CRANE CAMS, INC.
530 Fentress Blvd.
Daytona Beach,FL
32114-1200
Quik-Link #11067
DART MACHINERY
353 Oliver St.
Troy, MI 48084
Quik-Link #11068
DIAMOND RACING
PRODUCTS
23003 Diamond Dr.
Clinton Twp, MI 48035
Quik-Link #11056
HOLLEY PERFORMANCE PRODUCTS
1801 Russellville Rd.
Bowling Green, KY 42101
Quik-Link #11069
JESEL VALVETRAIN INC.
1985 Cedarbridge Ave.
Lakewood, NJ 08701
Quik-Link #11070
LUNATI
(see Holley Performance Products)
Quik-Link #11071
MAHLE MOTORSPORTS
270 Rutledge Rd., Unit B
Fletcher, NC 28732
Quik-Link #11060
MOROSO PERFORMANCE PRODUCTS
80 Carter Dr.
Guilford, CT 06437
Quik-Link #11072
MSD IGNITION
1490 Henry Brennan Dr.
El Paso, TX 79936-6805
Quik-Link #11073
Tags: ARP, ATI SUPER DAMPER, CAMSHAFT, CRANE, CRANK TRIGGER, DART, DART BIG CHIEF II HEAD SPECS, DIAMOND, DISTRIBUTOR, HOLLEY DOMINATOR, JESEL BELT DRIVE, JESEL ROCKERS, LUNATI, MAHLE CLEVITE, MEZIERE, MOROSO BILLET GEROTOR OIL PUMP, MOROSO OIL PAN, MSD, ROLLER LIFTERS, SPARK PLUG WIRES, VALVE COVERS, VICTOR MLS HEAD GASKETS
