AFR 23° SBC Cylinder Head 245cc Competition Package, Spread Port Exhaust, 80cc Chambers

The AFR 245cc SBC Race Cylinder Head is our largest and most powerful 60/40 head for the small block Chevy. Designed for maximum performance, it features fully CNC-machined intake runners, exhaust ports, and combustion chambers. Capable of flowing an impressive 350 CFM at 0.800" lift, this head is built for high-RPM racing applications. It comes equipped with premium components, including titanium retainers and PAC racing springs, ensuring top-tier durability and performance. The 60/40 valve spacing requires shaft-mounted rocker arms for optimal valve train geometry and includes extra machining for 3/8" pushrod clearance. The NPP (No Pushrod Pinch) design allows for maximum airflow efficiency.

Included Components

100% CNC Ported Combustion Chambers
100% CNC Ported Exhaust Ports
100% CNC Ported Intake Ports
Competition 5-angle Valve Job
8mm Bead Lock Intake Valve, 2.125" x 5.000" Overall Valve Length (AFR #7253)
8mm Bead Lock Exhaust Valve, 1.600" x 5.030" Overall Valve Length (AFR #7254)
PAC #1225 Racing Springs - 1.550” OD Solid Roller Dual Valve Drag Race Spring, 250 lbs. on seat, .800” max lift, Max RPM 8000-8200 (AFR #8001)
10° Titanium Retainers (AFR #8505)
10° Bead Lock Valve Keepers with Lashcap Recess (AFR #9009)
Viton Valve Seals (AFR #6612)
Hardened Valve Spring I.D. Locator (AFR #8048)
Ductile Iron Intake Valve Seats (AFR #9060)
Ductile Iron Exhaust Valve Seats (AFR #9070)
8mm Bronze Valve Guides (AFR #9051)

Performance Flow Chart

Test conducted at 28" of water (pressure) on Superflow 600. Bore Size: 4.155", intake 3/4" radius plate exhaust, 1 7/8" curved pipe.

Lift (in.)	.200	.300	.400	.500	.550	.600	.650	.700	.800
Intake CFM	161	224	261	301	311	320	331	337	345
Exhaust CFM	128	165	214	228	237	238	243	245	250

Technical Specifications

Material: A356 Aluminum
Intake Port Volume: 245cc
Exhaust Port Volume: 80cc
Combustion Chamber Size: 70cc or 80cc
Valve Angle: 23°
Deck Thickness: .750"
Minimum Bore Diameter: 4.000"
Valve Cover Bolt Pattern: Perimeter Bolt
Spark Plug Dimensions: 14mm x .750" w/Gasket Seat
Spring Pocket Diameter: 1.580" O.D (Max 1.680" O.D.)

Important Notes

Do not use your AFR gasket as a template to port match your intake manifold, as one AFR gasket is used for multiple runner volumes. Additionally, do not machine the spring pad any deeper than specified.

CARB Compliance Notice

THESE PRODUCTS ARE ILLEGAL TO OPERATE ON ANY PUBLIC HIGHWAY OR ROADWAY. These cylinder heads are intended for use on dedicated racing vehicles only. Violation of this regulation may result in penalties up to $37,500 per vehicle, revocation of registration by the DMV, and loss of use on public roadways.