AFR 15° LS Cathedral Port Cylinder Head 230cc Fully CNC Ported, 65cc Chambers, 5.7 Small Bore

The AFR 15° LS Cathedral Port Cylinder Head is designed for high-performance builds that demand maximum airflow and precision. Built from A356 aluminum, this cylinder head features a fully CNC-ported intake, exhaust, and combustion chambers, making it perfect for aggressive street and street/strip applications. Ideal for displacements up to 427 cubic inches operating at or below 7200 RPM, it flows 328 CFM at 0.650" lift with a 4.000" bore size.

Piston Specifications

Piston Top: Fully CNC ported combustion chambers
Approximate Compression Ratios:
- 62cc, 65cc, or 72cc chamber options
Engine Compatibility: Ideal for 5.7 Small Bore LS engines
Engine Sizes Supported: Up to 427 cubic inches

Technical Details

Material: A356 Aluminum
Intake Port Volume: 230cc
Exhaust Port Volume: 86cc
Valve Cover Bolt Pattern: Center Bolt
Valve Spring Pocket Diameter: 1.510" O.D
Deck Thickness: .750"
Minimum Bore Diameter: 3.900"
Spark Plug Dimensions: 14mm x .750" with Tapered Seat

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, 2.080" x 4.900" Overall Valve Length (AFR #7208)
8mm Bead Lock Exhaust Valve, 1.600" x 4.900" Overall Valve Length (AFR #7228)
PAC Racing Spring 1.270" OD Hydraulic Roller Dual Valve Spring, 155 lbs. on seat, .650” maximum lift, Max RPM 7000-7200 (AFR #8019)
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)
Ductile Iron Intake Valve Seats 2.131" O.D x 1.680" I.D x .375" Deep (AFR #9059)
Ductile Iron Exhaust Valve Seats 1.650" O.D x 1.350" I.D x .375" Deep (AFR #9069)
8 mm Bronze Valve Guides .502" O.D x 2.100" O.A.L (AFR #9051)

Performance & Compatibility

The AFR 230cc LS1 MONGOOSE cylinder heads are engineered to provide exceptional airflow for aggressive street and race builds. The heads support a wide range of high-performance components, ensuring top-tier reliability and power at high RPMs. With a proven flow chart at varying lift values, these heads offer an excellent balance between street and strip performance, making them a great choice for any high-performance LS engine.

Competition Flow Chart

Intake Flow:
- .200: 157 CFM
- .300: 224 CFM
- .400: 272 CFM
- .500: 311 CFM
- .550: 320 CFM
- .600: 324 CFM
Exhaust Flow:
- .200: 129 CFM
- .300: 183 CFM
- .400: 225 CFM
- .500: 244 CFM
- .550: 248 CFM
- .600: 252 CFM
Test conducted at 28" of water (pressure) on Superflow 600