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

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.