AFR 15° LS Cathedral Port Cylinder Head 205cc Fully CNC Ported, 66cc Chambers, 5.7 Small Bore

The AFR 205cc LS1 Cylinder Head is a cost-effective upgrade over reworked factory heads, featuring fully CNC ported intake and exhaust runners along with CNC-machined combustion chambers. Designed for street, street/strip, and towing applications, these heads are ideal for engines with displacements up to 383 cubic inches, operating at or below 6300 RPM. A minimum bore size of 3.900" is required to accommodate the 2.020" intake valve. Additionally, these heads are CARB-certified for use on 2005 and older emissions-controlled vehicles under EO #D-250-4.

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, 2.020” x 4.900" Overall Valve Length – AFR #7207
8mm Bead Lock Exhaust Valve, 1.600” x 4.900" Overall Valve Length – AFR #7228
PAC Racing Spring 1.290" OD Hydraulic Roller Dual Valve Spring (140 lbs seat pressure, .600" max lift, Max RPM 6300-6500) – AFR #8017
7° Titanium Retainers 1.245" O.D x .885" I.D x .655" I.D – AFR #8512
7° Bead Lock Valve Keepers – AFR #9007*
Viton Valve Seals .600" O.D x .495" I.D – AFR #6612
Hardened Valve Spring O.D Locator 1.380" O.D x .570" I.D – AFR #8042

205cc Competition Flow Chart

Lift (.in)	.200	.300	.400	.500	.550	.600
Intake (CFM)	147	214	249	284	296	301
Exhaust (CFM)	111	150	209	225	230	233

Specifications & Features

Material: A356 Aluminum
Intake Port Volume: 205cc
Intake Port Dimension: 3.275"H x 1.120"W
Exhaust Port Volume: 84cc
Exhaust Port Dimension: 1.415" H x 1.710" W
Combustion Chamber Size: 66cc
Valve Cover Bolt Pattern: Center Bolt
Valve Angle: 15°
Deck Thickness: .750"
Minimum Bore Diameter: 3.900"
Spark Plug Dimensions: 14mm x .750" w/Tapered Seat
CARB EO #: D-250-4

Performance & Compatibility

The AFR 205cc LS1 Cylinder Heads are built for reliable performance, offering superior airflow and combustion efficiency. The fully CNC-ported design ensures maximum power output while maintaining drivability, making them a great choice for high-performance street builds, towing applications, and track use. These heads are compatible with LS1/LS6-based applications and require a minimum bore size of 3.900" for proper fitment.