AFR 18° BBC Cylinder Head 457cc Fully CNC Ported, 90cc Chambers, Competition Package

The AFR 457cc 18° Big Block Chevy cylinder head is the ultimate performance upgrade for serious racers. These heads feature fully CNC-ported intake and exhaust runners along with 90cc combustion chambers for maximum efficiency and power. The intake ports are raised .500" with an 18° valve angle, delivering superior airflow and combustion efficiency. With stainless steel 2.400" intake and 1.800" exhaust valves, these heads are optimized for engines 540 cubic inches and larger. AFR also offers titanium valves and copper seats as optional upgrades.

Performance & Compatibility

Engine Compatibility: Ideal for 540CI or larger race engines
Valve Configuration: 2.400" stainless steel intake valves, 1.800" stainless steel exhaust valves
Valve Angle: 18° intake / 11° exhaust
Chamber Volume: 90cc
Required Components: Specific pistons, valve covers, shaft mount rockers, and compatible intake manifolds

Technical Details

Material: A356 Aluminum
Intake Port Volume: 457cc
Intake Port Dimensions: 2.490" H x 1.750" W x 1/2" Radius
Intake Port Location: .500" Raised
Exhaust Port Volume: 143cc
Exhaust Port Dimensions: 1.850" H x 2.090" W
Exhaust Port Location: .450" Raised
Valve Cover Bolt Pattern: Standard
Deck Thickness: .750"
Minimum Bore Diameter: 4.600"
Spark Plug Dimensions: 14mm x .750" with Tapered Seat
CARB Status: Not legal for sale or use on emission-controlled vehicles; intended for dedicated race vehicles only.

Basic Package Components

100% CNC Ported Intake Ports, Exhaust Ports, & Combustion Chamber
Competition 5-Angle Valve Job
Intake Valve: 2.400" X 6.035" O.A.L. 50° Seat (AFR #7420)
Exhaust Valve: 1.800" X 5.935" O.A.L. 55° Seat (AFR #7422)
Valve Springs: PAC Racing #1258 1.645” OD Solid Roller Triple Spring (350 lbs. on seat, .950” max lift, 8300-8500 RPM) (AFR #8014)
Retainers: 10° Titanium Retainer (AFR #8517)
Valve Keepers: 10° 11/32" Bead Lock with recess lashcaps (AFR #9010)
Valve Seals: 11/32" Viton (AFR #6613)
Spring Cup: Hardened 1.740 O.D X 1.677 I.D X .570 (AFR #9170)
Intake Valve Seats: 2.500" O.D X 2.000" I.D X .375" Deep (AFR #9162)
Exhaust Valve Seats: 1.900" O.D X 1.400" I.D X .375" Deep (AFR #9066)
Bronze Valve Guides: 11/32" .502" O.D X 2.700 O.A.L. (AFR #9055)
Exhaust Bronze Valve Guides: 11/32" .502" O.D x 2.25" O.A.L (AFR #9042)