AFR 24°BBC 300cc Oval Port Fully CNC Ported, 112cc chambers, Competition Package, Assembled w/1.550 OD Hydraulic Roller Springs

AFR 24° BBC 300cc Oval Port Fully CNC Ported Cylinder Head – Competition Package

Designed for aggressive street, street/strip, or race applications, the AFR 24° BBC 300cc Oval Port Cylinder Head is the ultimate performance upgrade for big block Chevy engines up to 540 cubic inches operating at or below 6800 RPM. Featuring 100% CNC-machined intake runners, exhaust ports, and combustion chambers, this competition-ready cylinder head flows an impressive 388 CFM at 0.700” lift—offering superior power without requiring a rectangular port design.

Included Components

• 100% CNC Ported Combustion Chambers
• 100% CNC Ported Exhaust Ports
• 100% CNC Ported Intake Ports
• Competition 5-Angle Valve Job
• Intake Valve: 11/32″, 2.300″ x 5.500″ O.A.L (AFR #7626)
• Exhaust Valve: 11/32″ Nail Head, 1.880″ x 5.450″ O.A.L (AFR #7630)
• Valve Springs: PAC Racing #1940 1.550″ OD Hydraulic Roller Dual Valve Spring (175 lbs. on seat, .725″ max lift, Max RPM 6500-6700) with #8511 Steel Retainer and #8044 Spring Cup (AFR #8002)
• Rocker Studs: ARP 7/16″ Intake (AFR #6407) & ARP 7/16″ Exhaust (AFR #6406)
• Valve Seals: 11/32″ Viton (AFR #6613)
• Guide Plates: Adjustable 3/8″ (AFR #6109)
• Valve Seats: Intake 2.450″ O.D x 1.950″ I.D x .375″ Deep (AFR #9065), Exhaust 2.000″ O.D x 1.580″ I.D x .375″ Deep (AFR #9064)

300cc Competition Flow Chart

Test conducted at 28″ of water (pressure) on Superflow 1020. Bore Size: 4.500″, 3/4″ radius plate exhaust, 1 7/8″ curved pipe.

Specifications & Features

• Material: A356 Aluminum
• Intake Port Volume: 300cc
• Combustion Chamber Size: 112cc (Full CNC)
• Exhaust Port Volume: 135cc
• Deck Thickness: .750″
• Valve Angle: 24°/4° Int, 15°/4° Exh
• Spark Plug Dimensions: 14mm x .750″ w/Gasket Seat
• CARB Status: Not legal for sale or use on emission-controlled vehicles—intended for dedicated race vehicles only.

Performance & Compatibility

The AFR 24° BBC 300cc Oval Port Cylinder Head is engineered for big block Chevy enthusiasts who demand the best in airflow efficiency and durability. Whether you’re running an aggressive street build, a street/strip setup, or a full race application, this cylinder head delivers high-performance results with exceptional reliability. Perfect for engines up to 540 cubic inches, it maximizes power and efficiency without sacrificing drivability.