Product Description
AFR 12° LS3 4-Bolt Cylinder Heads – 260cc CNC Ported | 69cc Chambers (Pair)
Fully Assembled Rectangle Port LS3 Heads | High-Performance Street & Race Applications
AFR’s 260cc LS3 Mongoose cylinder heads feature fully CNC-ported intake runners, exhaust runners, and combustion chambers engineered using advanced airflow modeling to deliver maximum performance. Manufactured from high-strength A356 aluminum and assembled with premium valvetrain components, these heads are designed for 4.000" and larger bore LS engines up to 454 cubic inches. Ideal for serious street builds and competitive racing applications, these AFR LS3 heads deliver exceptional airflow, durability, and combustion efficiency.
Included Components
- 100% CNC Ported Combustion Chambers – 69cc
- 100% CNC Ported Intake Ports – 260cc
- 100% CNC Ported Exhaust Ports – 95cc
- Competition 5-Angle Valve Job
- 8mm Bead Lock Intake Valves – 2.165" Diameter x 5.200" OAL
- 8mm Bead Lock Exhaust Valves – 1.600" Diameter x 5.205" OAL
- PAC Racing Dual Valve Springs – 155 lbs Seat Pressure, .650" Max Lift
- 7° Titanium Retainers
- 7° Bead Lock Valve Keepers
- Viton Valve Seals
- Hardened Valve Spring Locators
- Ductile Iron Intake & Exhaust Valve Seats
- 8mm Bronze Valve Guides
- AFR-Specific Rocker Stands (Required – Stock LS3 stands will not fit)
Specifications & Features
- Minimum Bore Diameter: 4.000"
- Material: A356 Aluminum
- Intake Port Volume: 260cc
- Intake Port Dimensions: 2.610" H x 1.300" W x 7/16° Radius
- Exhaust Port Volume: 95cc
- Exhaust Port Dimensions: 1.540" H x 1.760" W
- Combustion Chamber Size: 69cc
- Valve Angle: 12°
- Deck Thickness: .750"
- Valve Cover Bolt Pattern: Center Bolt
- Spark Plug Compatibility: 14mm x .750" Gasket Seat or 14mm x .708" Taper Seat
- Head Bolt Pattern: Standard LS 4-Bolt Per Cylinder
Heads are sold and priced as a matched pair.
