Our max effort cathedral port head for the LSX platform is recommended for race applications or radical "Pro Street" builds with displacements up to 454 cubic inches, operating at or below 6800 RPM. Requires a minimum bore size of 4.000" to clear the supplied 2.165" intake valve. CARB Legal for 2005 and older emissions controlled vehicles under CARB EO #D-250-4 with 65cc combustion chambers.
Basic Package 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 4.900" Overall Valve Length | |
8mm Bead Lock Exhaust Valve, 1.600" x 4.900" Overall Valve Length | |
PAC Racing Spring 1.270" OD Hydraulic Roller Dual Valve Spring, 155 lbs. on seat, .650” maximum lift, Max RPM 7000-7200 | |
7° Titanium Retainers 1.245" O.D x .885" I.D x .655" I.D | |
7° Bead Lock Valve Keepers | |
Viton Valve Seals .600" O.D x .495" I.D | |
Hardened Valve Spring O.D Locator 1.380" O.D x .570" I.D | |
Ductile Iron Intake Valve Seats 2.200" O.D x 1.750" I.D x .375" Deep | |
Ductile Iron Exhaust Valve Seats 1.650" O.D x 1.350" I.D x .375" Deep | |
8 mm Bronze Valve Guides .502" O.D x 2.100" O.A.L |
245cc Large Bore Competition Flow Chart | |||||||
.200 | .300 | .400 | .500 | .550 | .600 | .650 | |
Int | 164 | 233 | 290 | 332 | 347 | 356 | 360 |
Exh | 131 | 185 | 227 | 247 | 249 | 257 | 267 |
Test conducted at 28" of water (pressure) on Superflow 600
Bore Size: 4.155", intake 3/4" radius plate exhaust, 1 3/4" curved pipe
Specifications & Features: | |
Material |
A356 Aluminum
|
Intake Port Volume |
245cc
|
Intake Port Dimension |
3.315"H x 1.145"W x 11/32 top 13/32 bottom
|
Intake Port Location |
Stock
|
Exhaust Port Volume |
88cc
|
Exhaust Port Dimension |
1.495" H x 1.730" W
|
Exhaust Port Location |
Stock
|
Combustion Chamber Size |
65cc or 73cc
|
Valve Cover Bolt Pattern |
Center Bolt
|
Valve Angle |
15°
|
Valve Spring Pocket Diameter |
1.510" O.D
|
Max Valve Spring Pocket Machining |
1.525" O.D
|
Deck Thickness |
.750"
|
Minimum Bore Diameter |
4.000"
|
Flat Mill - 65cc chamber |
.006" per cc 58cc Maximum
|
Flat Mill - 73cc chamber |
.006" per cc 65cc Maximum
|
Minimum Cross Sectional Area |
2.680 sq. in.
|
Spark Plug Dimensions |
14mm x .750" w/Tapered Seat
|
CARB Status: This product is not legal for sale or use on emission-controlled vehicles and intended for dedicated race vehicles only. |
Recommended Components: | |
Intake Port Gasket |
GM or FAST
|
Exhaust Port Gasket |
GM #12558573
|
Head Gasket |
Cometic 4.200 .040" or AFR #6845
|
Head Bolts (97-03) |
ARP 134-3609 or AFR #6330
|
Head Studs (97-03) |
ARP 234-4110 or AFR #6331
|
Head Bolts (04+) |
ARP 134-3610 or AFR #6334
|
Head Studs (04+) |
ARP 234-4317 or AFR #6335
|
Head Bolt Washers, Manley | |
Suggested Manifold |
FAST 90mm, 92mm, or 102mm
|
Spark Plug Starting Range |
NGK TR55
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