AFR LS3 69cc Chamber 6-Bolt 260cc CNC Ported Cylinder Heads
Highlights
- 260cc CNC Ported Heads
- Large Bore LS Performance
- 6-Bolt Block Compatible
- Race Ready Assembly
Pair of AFR LS3 6-Bolt 260cc Fully CNC Ported Cylinder Heads with 69cc Chambers for 1960-1987 Chevy C10s and 1988-1998 Chevy C/K Trucks with Large Bore LS Engines.
Maximize airflow and horsepower potential with these cylinder heads designed for serious performance applications. They are ideal for engines up to 454 cubic inches operating at engine speeds approaching 7000 RPM. Precision-engineered for 6-bolt block configurations commonly found on aftermarket LS blocks, these heads deliver race-proven airflow with excellent durability. Each head features 100% CNC ported intake ports, exhaust ports, and combustion chambers to ensure consistent performance.
Features and Benefits:
- Fully CNC ported intake, exhaust, and chambers
- 260cc rectangle port intake design
- 69cc combustion chambers for performance builds
- 12-degree valve angle improves airflow efficiency
- PAC dual valve springs support high RPM operation
- Stainless steel intake and exhaust valves
- Premium valvetrain components preassembled
- Fits 6-bolt LS block configurations
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 5.200" overall valve length
- 8mm bead lock exhaust valve, 1.600" x 5.205" 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 2.550" OAL
Specifications:
- Material: A356 aluminum
- Intake port dimensions: 2.610" H x 1.300" W x 7/16
- Intake and exhaust port location: Stock
- Exhaust port volume: 95cc
- Exhaust port dimensions: 1.540" H x 1.760" W
- Valve cover bolt pattern: Center bolt
- Valve angle: 12 degrees
- Valve spring pocket diameter: 1.490" OD
- Max valve spring pocket machining: 1.510" OD
- Deck thickness: .750"
- Minimum bore diameter: 4.000"
- Flat mill: 65cc chamber, .006" per cc, 62cc maximum
- Minimum cross-sectional area: 2.875 sq. in.
- Spark plug dimensions: 14mm x .750" with tapered seat
Recommended Components:
- Head gasket: Cometic 4.160" x .040"
- Intake port gasket: GM or aftermarket
- Exhaust port gasket: GM #12558573
- Head bolts: (04+) ARP #134-3610
- Head studs: (04+) ARP #234-4316
- Head bolt washers: Manley AFR #6320
- Suggested intake manifold: FAST 92mm or 102mm
- Spark plug starting range: NGK TR55
- Recommended rockers: Factory with trunnion upgrade or Yella Terra #6733 with #5132 valves
Vehicle Fitment:
- 1960-1987 Chevy C10s
- 1988-1998 Chevy C/K Trucks
California Residents: Proposition 65 Warning
Related Categories: C10 Cylinder Heads, C10 Restomod Engine, C/K Engine, C/K Restomod
Only for use on pre-pollution controlled vehicles: This product can be used on vehicles that were manufactured before emissions control regulations were imposed. Pre-pollution vehicles are defined as:
- 1965 and older U.S. manufactured California certified vehicles
- 1967 and older U.S. manufactured federally certified vehicles
