gmparts_title1.gif (1087 bytes)LT4 HEADS

 

The following related components are recommended when installing GMPerformance Parts Corvette aluminum cylinder head assemblies:

head3.jpg (8737 bytes)

Part Number Description
12555269 Stamped steel rocker cover
10229162 Corvette screw-in oil filler cap
12342056 Chrome screw in oil cap w/GM logo
12338092 Valve cover hold-down bolts (8 required)
14094717 Hold-down bolt washers (8 required)
14088793 Hold-down bolt gaskets (8 required)
14088564 Neoprene rocker cover gasket
12557236 Composition head gasket, .051" thick
12495499 Head Bolt Kit
12495490 Rocker Arm Kit
12363287 — LT4 Design Aluminum Cylinder Head
This aluminum LT4 design head is the same as the 1996 production head except it has the LT1 rocker stud P/N 12552126 installed. This head has light weight 2.00" intake and 1.55" exhaust valves installed in this assembly. These heads can only be used on 1992 and later LT1 and LT4 engines.
NOTE: This head assembly includes the following items, intake valve P/N 12555331, exhaust valve P/N 12551313, valve spring P/N 12551483, valve cap P/N 10212808, seal P/N 10212810, key P/N 24503856, stud P/N 12552126, and shim P/N 10212809.
P/N DESC CSTNG NUMBER MAT'L INTAKE RUNNER VOLUME
(cc)
COMB CHAMBER VOLUME
(cc)
VALVE DIAMETER SPRK PLUGS HEAT RISERS NOTES
12363287 LT4 SERVICE ONLY NA ALUM 195 54.4 I: 2.00"
E: 1.55"
Angled No For LT1 or LT4 usage only
GROUP 0.296 INTAKE VALVES
12551313 — Exhaust Valve 1.55" Diameter
These 1.55" exhaust valves are used in the 1996 350 LT4 Corvette.
12555331 — Intake Valve 2.00" Diameter
These 2.00" intake valves are used in the 1996 350 LT4 Corvette.
VALVE SPRINGS — SMALL-BLOCK V8 AND V6/90°QUICK REFERENCE CHART
PN DESC OUTSIDE DIAMETER PRESSSURE AT INTALLED HEIGHT SOLID HEIGHT AVERAGE RATE (# per in) RETAINER PN VALVE SEAL KIT NOTES
10206040 Single Spring 1.30" 85# @ 1.78" 1.26" 373 10168424 NA LT1 production Corvette
engine.
12551483 Single Spring 1.32" 101# @ 1.78" 1.22" 332 10212808 NA 1996 LT4 Corvette and ZZ4 engines.
10212810 — Valve Stem Seal LT4
These valve stem seals are used on 1996 350 LT4 engines and specialperformance LT4 design service heads.
10212809 —Valve Spring Shim LT4
These valve spring shims are used on 1996 LT4 Corvette engines as well as the special LT service-only heads P/N 12363287. These are light weight caps Technical Note: Use with spring P/N 12551483.
10168424 — Valve Spring Cap
Used on 1992-93 Corvette LT1 engines. This lightweight cap is to be used with spring P/N 10206040.
12495492 — Valve Spring Cap Kit, LT4
This valve spring cap kit which includes 16 of P/N 10212808 caps, is used on all 5.7L LT4 engines. These are light weight caps to be used with valve spring kit P/N 12495494, and key kit P/N 12495503.
10212808 — Valve Spring Cap LT4 - ZZ4
These valve spring caps are used on 1996 LT4 Corvette ZZ4 engines as well as the special service only heads P/N 12556463. These are light weight caps.
Technical Note: Use with spring P/N 12551483.


ADDITIONAL TECH INFORMATION
LT4 Longblock LT1 / LT4 variables GMPP LT4 heads LT1 vs LT4 Vette
Rebuilding the LT1 Cam Selection R&R Head Flow Comparo HOME 96Legacy