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Old 01-07-2016, 10:23 AM   #5
Russell James


 
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Drives: '15 SS 1LE, '69 Z28 drag car
Join Date: Dec 2009
Location: Mich
Posts: 4,482
L92/LS3/L99 are all the same head casting. Same port sizes, chamber size, valve size.. There were a couple casting numbers used over the years... but are the same and interchangeable.

The differences are the springs and valves. LS3 uses a stiffer spring, and lighter hollow valve. The difference in compression between the 3 engines is due to the valve reliefs in the piston. LS3 is a flat top piston, and has the highest compression and hp. The VVT engines require piston valve reliefs.

So, you just need to match the spring and valve to the engine it is going on.
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