AFR LS3 69cc Chamber 4-Bolt 260cc CNC Ported Cylinder Heads
Highlights
- 260cc CNC Ported Heads
- Large Bore LS Performance
- 4-Bolt Block Compatible
- Race Ready Assembly
Pair of AFR LS3 4-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.
These cylinder heads enhance the airflow and horsepower potential of your classic ride. They are ideal for LS builds and 4-bolt block configurations. Each head features 100% CNC ported intake ports, exhaust ports, and combustion chambers to ensure consistent performance. The 12-degree valve angle, 69cc chambers, and competition 5-angle valve job promote better efficiency and strong cylinder filling at high lift. The heads come fully assembled for hassle-free upgrading.
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 4-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
