AFR’s 260cc LS3 “Mongoose” heads feature 100% CNC ported intake, exhaust and chambers using our advanced engineering and flow techniques to produce the ultimate Rectangle Port head available today. Featuring A356 aluminum castings, titanium retainers and the highest quality components, throughout. They’re designed for 4.000 or larger bore applications up to 454 CI, operating up to 7000 RPM. Emmisons legal for 2008 to 2015 vehicles under CARB #D-250-5.
260cc Street Head Flow Chart
.200 .300 .400 .500 .600 .650 .700
Int 159 234 293 336 366 377 384
Exh 112 158 207 235 248 251 255
Test conducted at 28" of water (pressure) on Superflow 600
Bore Size: 4.155", 3/4" radius plate exhaust, 1 3/4" curved pipe
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, 2.165" x 5.195" Overall Valve Length: AFR #7214
- 8mm Bead Lock Exhaust Valve, 1.600" x 5.200" Overall Valve Length: AFR #7212
- PAC Racing Spring 1.270" OD Hydraulic Roller Dual Valve Spring, 155 lbs. on seat, 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 2.200" O.D x 1.750" I.D x .375" Deep: AFR #9060
- 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 2.550" O.A.L: AFR #9053
- Rocker Rail Stand: AFR #6040
Recommended Components:
Intake Port Gasket: Factory GM or Aftermarket
Exhaust Port Gasket: GM #12558573
Head Gasket: Cometic 4.160 Bore Size
Spark Plug Starting Range: NGK TR55
Specifications & Features:
- Material: A356 Aluminum
- Intake Port Volume: 260cc
- Intake Port Dimension: 2.610"H x 1.300"W x 7/16° Radius
- Intake Port Location: Stock
- Exhaust Port Volume: 95cc
- Exhaust Port Dimension: 1.540" H x 1.760" W
- Exhaust Port Location: Stock
- Combustion Chamber Size: 69cc
- Valve Cover Bolt Pattern: Center Bolt
- Valve Angle: 12°
- Valve Spring Pocket Diameter: 1.490" O.D
- Max Valve Spring Pocket Machining: 1.510" O.D
- 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" w/Gasket Seat
- Carb EO#: D-250-5
