AFR 24° BBC Cylinder Head 265cc Oval Port - Partially CNC Ported, 109cc Chambers, Race Ready, Complete w/Hydraulic Roller Springs

The AFR 265cc BBC Oval Port Cylinder Head is an excellent choice for those seeking a high-velocity, small-port cylinder head that outperforms factory big block Chevy heads. Designed for street, street/strip, and towing applications, this torque monster flows up to 354 CFM at 0.650" lift and is suitable for engines up to 468 cubic inches operating at or below 6200 RPM. The intake runners and exhaust ports are partially CNC-machined, while the combustion chambers are available with partial or full CNC machining with a bowl blend for optimized performance.

Key Features

265cc Intake Port Volume - High-Velocity Oval Port Design
Partially CNC-Ported Intake and Exhaust Runners with Bowl Blend
Available with 75% CNC-Ported Exhaust Ports & 75% CNC Chambers
Supports Displacements Up to 468 CID & 6200 RPM Limit
Ideal for Street/Strip & Towing Applications
Durable A356 Aluminum Construction

Flow Data

Test conducted at 28" of water on Superflow 1020 with a 4.310" bore size.

265cc As Cast Flow Chart

Lift	Intake (CFM)	Exhaust (CFM)
.200	154	127
.300	218	164
.400	278	200
.500	323	230
.550	330	250
.600	333	255
.650	335	260

265cc w/ 100% CNC Chamber Flow Chart

Lift	Intake (CFM)	Exhaust (CFM)
.200	164	135
.300	236	190
.400	291	230
.500	326	258
.550	330	265
.600	335	274
.650	340	280

Specifications & Features

Material: A356 Aluminum
Intake Port Volume: 265cc
Exhaust Port Volume: 132cc
Combustion Chamber Size: 109cc (Partial CNC), 112cc (Full CNC)
Valve Angle: 24°/4° Intake, 15°/4° Exhaust
Deck Thickness: .750"
Minimum Bore Diameter: 4.125"
Valve Cover Bolt Pattern: Perimeter Bolt
Spark Plug Dimensions: 14mm x .750" w/Gasket Seat

Included Components

11/32" Intake Valve, 2.190" x 5.460" - AFR #7601
11/32" Nail Head Exhaust Valve, 1.880" x 5.450" - AFR #7630
PAC Racing Springs (Hydraulic Roller Dual Valve Spring, 175 lbs. seat, .725” max lift) - AFR #8002
10° Steel Retainers, 1.500" O.D - AFR #8511
ARP 7/16" Rocker Studs (Intake & Exhaust) - AFR #6407 / #6406
Adjustable 3/8" Guide Plates - AFR #6109
11/32" Viton Valve Seals - AFR #6613
Hardened Valve Spring Cup & Locator - AFR #8044 / #8048

Performance & Compliance

This product is not legal for use on public highways or roadways. It is intended for dedicated racing applications only. Violation of this regulation may result in fines and penalties.