245cc LSX "Mongoose" Competition Head
Our Max Effort Cathedral Port Offering
AFR's 245cc LSX "Competition" ported heads feature 100% CNC ported intake, exhaust & chambers, A356 aluminum castings, Titanium retainers and high quality components throughout. Recommended for race applications or radical "Pro Street" style builds with displacements up to 454 cubic inches, operating up to 6800 RPM. Requires minimum 4.000 bore size for intake valve clearance. Part numbers with an asterisk are legal for 2005 and older emissions controlled vehicles under CARB EO #D-250-4.
245cc Large Bore LSX Aluminum Cylinder Head Flow Chart
Tested on 4.155 bore
Basic Package Components
100% CNC Ported Combustion Chambers
100% CNC Ported Exhaust Ports
100% CNC Ported Intake Ports
Competition 5-angle Valve Job
AFR #72118mm Bead Lock Intake Valve, 2.165" x 4.900" Overall Valve Length
AFR #72288mm Bead Lock Exhaust Valve, 1.600" x 4.900" Overall Valve Length
AFR #8019PAC Racing Spring 1.270" OD Hydraulic Roller Dual Valve Spring, 155 lbs. on seat, Max RPM 7000-7200
AFR #85127° Titanium Retainers 1.245" O.D x .885" I.D x .655" I.D
AFR #9007*7° Bead Lock Valve Keepers
AFR #6612Viton Valve Seals .600" O.D x .495" I.D
AFR #8042Hardened Valve Spring O.D Locator 1.380" O.D x .570" I.D
AFR #9060Ductile Iron Intake Valve Seats 2.200" O.D x 1.750" I.D x .375" Deep
AFR #9069Ductile Iron Exhaust Valve Seats 1.650" O.D x 1.350" I.D x .375" Deep
AFR #90518 mm Bronze Valve Guides .502" O.D x 2.100" O.A.L
*LSX bead locks and aftermarket bead locks are not interchangeable. GM made their bead lock radius and depth different. AFR locks are the same as GM LSX.
Specifications & Features:
A356 AluminumMaterial
245ccIntake Port Volume
3.315"H x 1.145"W x 11/32 top 13/32 bottomIntake Port Dimension
StockIntake Port Location
88ccExhaust Port Volume
1.495" H x 1.730" WExhaust Port Dimension
StockExhaust Port Location
65cc or 73ccCombustion Chamber Size
Center BoltValve Cover Bolt Pattern
15°Valve Angle
1.510" O.DValve Spring Pocket Diameter
1.525" O.DMax Valve Spring Pocket Machining
.750"Deck Thickness
4.000"Minimum Bore Diameter
.006" per cc 58cc MaximumFlat Mill - 65cc chamber
.006" per cc 65cc MaximumFlat Mill - 73cc chamber
2.680 sq. in. Minimum Cross Sectional Area
14mm x .750" w/Gasket SeatSpark Plug Dimensions
D-250-4Carb EO#
Recommended Components:
GM or FASTIntake Port Gasket
GM #12558573Exhaust Port Gasket
AFR #6845Head Gasket, Cometic 4.200 .040"
AFR #6330Head Bolts (97-03), ARP 134-3609
AFR #6331Head Studs (97-03), ARP 234-4110
AFR #6334Head Bolts (04+), ARP 134-3610
AFR #6335Head Studs (04+), ARP 234-4317
AFR #6320Head Bolt Washers, Manley
FAST 90mm, 92mm, or 102mmSuggested Manifold
NGK TR55Spark Plug Starting Range