Dart Machinery Big Chief Pro-1 Aluminum Chev BB Head These 18 degree heads have what it takes to win, spread intake ports, shallow valve angles, efficient combustion chambers, raised exhaust runners, and a valvetrain that's reliable at high rpm. Huge 421cc intake runners maximize flow. These heads have as cast runners with CNC machined chambers and CNC blended bowls. Note: Must use specific pistons, intake, and shaft rockers.
Part Type: Cylinder Head Application: Chevrolet Big Block Cylinder Head Material: Aluminum Bare or Assembled: Bare Combustion Chamber Size: 100cc CNC Machined Combustion Chambers: Yes Intake Valve Angle: 18 Exhaust Valve Angle: 9 Intake Port Volume: 424cc CNC Machined Intake Port: No Intake Port Flow: 455cfm @ .900" Lift/ 28" Intake Port Location: Standard Intake Port Shape: Rectangular Intake Port Dimensions: 1.890" x 2.530" Suggested Intake Gaskets: Fel-Pro 1298 or Equivalent Exhaust Port Volume: 185cc CNC Machined Exhaust Port: No Exhaust Port Flow: 325 cfm @ .900" Lift/ 28" Exhaust Port Location: Raised .900" Exhaust Port Shape: Square Exhaust Port Dimensions: 2.100" x 1.800" Suggested Exhaust Gaskets: Fel-Pro 1490 or Equivalent Suggested Spark Plug: .750" reach Valve Guides: Manganese Bronze Valve Guide Spacing: Widened for use on min. 4.500" bore Valve Stem Diameter: 11/32" (.3415") Valve Seats: Ductile Iron Valve Job: Multi-Angle Intake Valve Diameter: 2.400" Intake Valve Included: No Exhaust Valve Diameter: 1.900" Exhaust Valve Included: No Suggested Valve Length: Intake: 6.600", Exhaust: 6.380" Valve Spring Pockets: 1.740" O.D. (.030" deeper MAX.) Valve Springs Included: No Valve Spring Application: NA Valve Springs Retainers Included: No Valve Locks Included: No Valve Seals Included: No Rocker Studs Included: No Guide Plates Included: No Valve Cover Mounting Style: Perimeter bolt Steam Holes Drilled: No Heat Crossover: No Suggested Head Bolts: ARP 135-3603 Suggested Head Studs: ARP 235-4103 Suggested Stud Girdle: Power Products 13602K, Howards Cams 90121, Jomar 1114 Head Bolt Torque with Oil: 70 ft./lbs. Rocker Stud Torque with Oil: Intake Bolt Torque with Oil: 35 ft./lbs. Manufacturer: Dart Machinery Manufacturer's Part Number: 18474030 Weight: 42 lbs. Warranty: Race Application, No warranty expressed or implied Quantity: Sold as Each
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