AFR 24° BBC Cylinder Head 305cc Partially CNC Ported, 117cc Chambers, Race Ready

AFR 24° BBC Cylinder Head 305cc Partially CNC Ported, 117cc Chambers, Race Ready

The AFR 305cc BBC Rectangle Port Cylinder Head is engineered for moderate street or street/strip applications, supporting displacements up to 509 cubic inches while operating at or below 6500 RPM. This high-performance cylinder head features partially CNC-machined intake and exhaust ports, with combustion chambers available in either partial or full CNC machining, including a precision bowl blend. Capable of flowing up to 368 CFM at 0.700″ lift, this head delivers excellent power and efficiency.

Included Components

• 50% CNC Ported Combustion Chambers
• 20% CNC Ported Exhaust Ports
• 30% CNC Ported Intake Ports
• Competition 5-Angle Valve Job
• 11/32″ Intake Valve (2.250″ x 5.500″ O.A.L) – AFR #7620
• 11/32″ Nail Head Exhaust Valve (1.880″ x 5.450″ O.A.L) – AFR #7630
• PAC Racing #1224 1.625” OD Solid Roller Dual Valve Spring (275 lbs. on seat, .850” max lift, Max RPM 7400-7600) – AFR #8031
• 10° Steel Retainers – AFR #8518
• 10° 11/32” Valve Keepers with Lashcap Recess – AFR #9005
• ARP 7/16” Rocker Studs (Intake) – AFR #6407
• ARP 7/16” Rocker Studs (Exhaust) – AFR #6406
• Adjustable 3/8″ Guide Plates – AFR #6109
• 11/32″ Viton Valve Seals – AFR #6613
• Hardened Spring Cup (1.740″ O.D / 1.650″ I.D) – AFR #8046
• Intake Valve Seats (2.450″ O.D x 2.000″ I.D x .375″ Deep) – AFR #9065
• Exhaust Valve Seats (2.000″ O.D x 1.580″ I.D x .375″ Deep) – AFR #9064
• 11/32″ Intake Bronze Valve Guides (.502″ O.D x 2.10″ O.A.L) – AFR #9041
• 11/32″ Exhaust Bronze Valve Guides (.502″ O.D x 2.25″ O.A.L) – AFR #9042

Performance Flow Chart

**305cc As Cast Flow Chart (CFM @ Lift)**

Specifications & Features

• Material: A356 Aluminum
• Intake Port Volume: 305cc
• Combustion Chamber Size: 117cc (as cast) / 121cc (full CNC)
• Valve Angle: 24°/4° Int, 15°/4° Exh
• Deck Thickness: .750″
• Minimum Bore Diameter: 4.250″
• Spark Plug Dimensions: 14mm x .750″ w/Gasket Seat

CARB Compliance Notice

THIS PRODUCT IS NOT LEGAL FOR USE ON PUBLIC HIGHWAYS. These cylinder heads are only intended for dedicated race vehicles. Violation of this restriction may result in penalties up to $37,500 per violation, DMV registration revocation, and proof of correction requirements.