AFR 65cc Chamber LS Cathedral Port Large Bore 245cc CNC Ported Cylinder Heads

These cylinder heads (1680) deliver serious power in your LS engine and are an excellent complement to high-output street and race applications. They feature fully CNC ported 245cc intake runners and 65cc combustion chambers to support large displacement LS builds up to 454 cubic inches operating at high RPM ranges. Each head is CNC machined throughout the intake ports, exhaust ports, and combustion chambers to promote consistent airflow and efficient combustion.

Features and Benefits:
- Fully CNC ported intake, exhaust, and chambers
- 245cc intake ports support high horsepower builds
- 65cc combustion chambers balance compression
- Large 2.165" intake valves improve airflow
- CNC 5-angle valve job enhances sealing
- PAC dual valve springs support high RPM operation
- Cathedral port design retains stock port location
- Assembled and ready for installation
- Designed for large bore LS engines

Kit Includes:
- 100% CNC ported combustion chambers
- 100% CNC ported intake and exhaust ports
- Competition 5-angle valve job
- 8mm bead lock intake valve, 2.165" x 4.900" overall valve length
- 8mm bead lock exhaust valve, 1.600" x 4.900" overall valve length
- PAC racing spring 1.270" OD hydraulic roller dual valve spring, 155 lbs on seat, .650" maximum lift, 7000-7200 max RPM
- 7-degree chrome moly retainers 1.245" OD x .885" ID x .655" ID
- 7-degree bead lock valve keepers
- Viton valve seals .600" OD x .495" ID
- Hardened valve spring OD locator 1.380" OD x .570" ID
- Ductile iron intake valve seats 2.200" OD x 1.750" ID x .375" deep
- Ductile iron exhaust valve seats 1.650" OD x 1.350" ID x .375" deep
- 8 mm bronze valve guides .502" OD x 2.100" OAL

Specifications:
- Material: A356 aluminum
- Intake port dimensions: 3.315" H x 1.145" W (11/32 top, 13/32 bottom)
- Intake and exhaust port location: Stock
- Exhaust port volume: 88cc
- Exhaust port dimensions: 1.495" H x 1.730" W
- Valve cover bolt pattern: Center bolt
- Valve angle: 15 degrees
- Valve spring pocket diameter: 1.510" OD
- Max valve spring pocket machining: 1.525" OD
- Deck thickness: .750"
- Minimum bore diameter: 4.000"
- Flat mill: 65cc chamber, .006" per cc, 58cc maximum
- Minimum cross-sectional area: 2.680 sq. in.
- Spark plug dimensions: 14mm x .750" with tapered seat

Recommended Components:
- Head gasket: Cometic 4.200" x .040" or AFR #6845
- Intake port gasket: GM or FAST
- Exhaust port gasket: GM #12558573
- Head bolts: (97-03) AFR #6330 or (04+) AFR #6334
- Head studs: (97-03) AFR #6331 or (04+) AFR #6335
- Head bolt washers: Manley AFR #6320
- Suggested intake manifold: FAST 90mm, 92mm, or 102mm
- Spark plug starting range: NGK TR55

Vehicle Fitment:
- 1960-1987 Chevy C10s
- 1988-1998 Chevy C/K Trucks