JEGS 555-514071 Big Block Chevy Aluminum Cylinder Head Features:

• 24-degree/4-degree intake valve angle
• 15-degree/4-degree exhaust valve angle
• Requires Guide plates, sold separately, we recommend Dart 27001230-4 or AFR 6110-1
• Requires 7/16 in. Rocker Arm Studs, sold separately
• Intake Port Location: Stock
• Intake Port Dimensions: 2.510 in. x 1.820 in. x 3/8 in. Radius
• Exhaust Port Location: 0.357 in. Raised
• Exhaust Port Dimensions: 1.690 in. x 1.900 in.
• Exhaust Port Volume: 140 cc
• Valve Seats Machined: Yes
• Valve Seat Machine Style: 3-Angle
• Valve Seat Material: Hardened Ductile Iron
• Valve Spring Pocket Diameter: 1.750 in. OD (Max Machining)
• Valve Spring Diameter: 1.460 in.
• Intake and Exhaust Valve Material: Stainless Steel
• Intake Valve Head Diameter: 2.250 in.
• Intake Valve Stem Diameter: .3415 in. - 11/32 in.
• Exhaust Valve Head Diameter: 1.880 in.
• Exhaust Valve Stem Diameter: .3415 in. - 11/32 in.
• Valve Length: Intake = +0.100 in. Longer than stock/ Exhaust = Stock Length
• Valve Locks: 7-degree
• Valve Retainers: Chromoly
• Intake Valve Guide Material: Manganese Bronze
• Exhaust Valve Guide Material: Phosphor Bronze
• Valve Guide Size: 1/2 in.
• Valve Guide clearance: .0014 in. - .002 in. (with 0.3415 in. Diameter valve stem)
• Spark Plug Dimensions: 14 mm x 0.750 in. with Gasket Seat
• Drilled for accessory hole

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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