AFR 24° BBC Cylinder Head 325cc Partially CNC Ported, Race Ready, w/121cc CNC Chambers

The AFR 325cc BBC Rectangle Port Cylinder Head is designed for aggressive street and street/strip big block Chevy applications with displacements up to 540 cubic inches, operating at or below 6800 RPM. Featuring partially CNC-machined intake and exhaust ports, along with fully or partially CNC-machined combustion chambers, this head delivers outstanding airflow performance, reaching 390 CFM at 0.700" lift.

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" Nail Head Exhaust Valve, 1.880" x 5.450" O.A.L – AFR #7631
PAC Racing #1224 1.625” OD Solid Roller Dual Valve Spring, 275 lbs. on seat, .850” maximum lift, Max RPM 7400-7600 – AFR #8031
10° Steel Retainers 1.500" O.D x 1.168" I.D x .844" I.D – AFR #8518
10° 11/32" Valve Keepers with lash cap 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 (325cc w/ 100% CNC Chamber)

Lift	.200	.300	.400	.500	.600	.700
Intake (CFM)	155	227	281	319	346	368
Exhaust (CFM)	135	195	240	254	262	266

Specifications & Features

Material: A356 Aluminum
Intake Port Volume: 325cc
Exhaust Port Volume: 132cc
Combustion Chamber Size: 117cc (As Cast) / 121cc (Full CNC)
Valve Angle: 24°/4° Intake, 15°/4° Exhaust
Deck Thickness: .750"
Minimum Bore Diameter: 4.250"
Spark Plug Dimensions: 14mm x .750" w/ Gasket Seat

Important Notice

CARB Status: These products are illegal to operate on any public highway, road, or park. They are only legal for use on dedicated racing vehicles. Violations are subject to fines up to $37,500 per violation per vehicle, possible revocation of registration, and loss of public road usage rights.