AFR 24° BBC Cylinder Head 345cc Partially CNC Ported, Race Ready, w/121cc CNC Chambers

AFR's 345cc BBC cylinder head is designed for radical street/strip, "Pro Street," and racing applications with engines up to 572 cubic inches, operating at or below 7000 RPM. Featuring partially CNC-machined intake runners and exhaust ports, these heads offer optimal airflow and efficiency. The combustion chambers are available with partial or full CNC machining, including a precision bowl blend, delivering exceptional performance. These heads flow up to 401 CFM at 0.700" of lift, making them a powerhouse for high-performance builds.

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, 2.300" x 5.500" O.A.L – AFR #7626
11/32" Tulip Exhaust Valve, 1.880" x 5.450" O.A.L – AFR #7631
PAC Racing #1224 1.625” OD Solid Roller Dual Valve Spring (Max RPM 7400-7600) – AFR #8031
10° Steel Retainers – AFR #8518
10° 11/32" Valve Locks 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

Airflow Performance

AFR's 345cc BBC cylinder heads undergo rigorous flow testing at 28" of water (pressure) on a Superflow 1020 using a 4.500" bore size. Below are the flow chart results for both partial and full CNC chamber options.

345cc BBC Partial CNC Chamber Flow Chart

Lift	.200	.300	.400	.500	.600	.700
Intake	149	221	280	322	360	382
Exhaust	129	184	222	251	259	264

345cc BBC Full CNC Chamber Flow Chart

Lift	.200	.300	.400	.500	.600	.700
Intake	157	231	289	336	365	375
Exhaust	138	193	236	253	262	266

Specifications & Features

Material: A356 Aluminum
Intake Port Volume: 345cc
Exhaust Port Volume: 132cc
Combustion Chamber Size: 121cc (Full CNC)
Valve Angle: 24°/4° Intake, 15°/4° Exhaust
Deck Thickness: .750"

CARB Compliance Notice

These cylinder heads are for off-road and racing use only. They are illegal for operation on any public highway and may result in penalties if used improperly.