Cylinder Head Specifications

• Material: A-356 Virgin Aluminum
• Intake Port Volume: 327 cc - Rectangle Port
• Combustion Chamber Volume: 115 cc
• Valve Angle: 24 and 4 Degree Intake, 15 and 4 Degree Exhaust
• Valve Sizes: 2.300 in. Intake / 1.880 in. Exhaust (11/32 in. Stem Diameter)
• Valve Springs: 1.550 in. Diameter; 240 lbs. Seat Pressure
• Steel Valve Retainers
• Raised Valve Cover Rail
• Spark Plug Configuration: Angled
• Drilled Accessory Bolt Holes

Facts and Related Components

• Torque Heads: 70 ft-lb.
• Torque Rocker Studs: 40-45 ft-lb.
• Intake Gasket: Brodix 158-MG2001, Fel-Pro 375-1252-3
• Head Gasket
  • 4.540 in. Bore - Fel-Pro 375-1017, Cometic 245-C5433
  • 4.600 in. Bore - Fel-Pro 375-1057, Cometic 245-C5434
• Exhaust Gasket: Fel-Pro 375-1411, Cometic 245-C5429
• Head Bolts: ARP 070-135-3606 or Manley 660-42192 Bolts & 660-42102 Washers
• Head Studs: ARP 070-235-4702 (12-point)
• Spark Plug Specs: 14 mm Thread, .750 in. (3/4) Reach, Gasket Seat
  • Racing gas start with NGK 739-R5671A-9
  • Alcohol start with NGK 739-R5671A-10
• Angle Milling: .0066 in. per cc
• Flat Milling: .0050 in. per cc
• Pushrod Slots: Standard
• Pushrods: Check pushrod clearance with head installed on the engine block before final assembly
• Stud Girdle: Standard, Brodix 158-1230
• Rocker Arms: Standard
• Lifters: Standard
• Pistons: 2 Degree Valve Rolled Piston
• Exhaust Pattern: Raised .600 in.
• Spring Pockets: May not be cut any larger or deeper than 1.625 in.
• Recommended Intake Manifold: Brodix BM 2017* (158-BM2017), BM 2027* (158-BM2027) - *Note: Oval Port Intake Manifold Must Be Port Matched to Fit Rectangular Port Heads

Flow (CFM @ 28 in. H20)

• Intake (Lift in. - CFM Flow)
  • 0.200 - 163
  • 0.300 - 237
  • 0.400 - 307
  • 0.500 - 361
  • 0.600 - 401
  • 0.700 - 406
  • 0.800 - 401
• Exhaust (Inches of Lift - CFM Flow)
  • 0.200 - 128
  • 0.300 - 173
  • 0.400 - 215
  • 0.500 - 247
  • 0.600 - 270
  • 0.700 - 280
  • 0.800 - 283

Emissions Note:

This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

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