LS3 head shrouding on 4.000 vs 4.030 vs 4.065
#1
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LS3 head shrouding on 4.000 vs 4.030 vs 4.065
Does anyone have any power comparisons between similar combos where the only difference is the bore? I'm mainly interested in 4.030 vs 4.065.
#3
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The combustion chamber shape and the bore diameter are extensions of the
port in a sense with the valve in the way. Obviously the larger the valve the
more important the chamber and bore become. The only true way to test for
what you're asking is to reduce the stroke in order to maintain identical cubic
inches since 6-7 cubes can easily increase 8-10 horsepower alone. Just know
that an increase in bore diameter WILL help low and midlift flow when a 2.165"
valve is used.
port in a sense with the valve in the way. Obviously the larger the valve the
more important the chamber and bore become. The only true way to test for
what you're asking is to reduce the stroke in order to maintain identical cubic
inches since 6-7 cubes can easily increase 8-10 horsepower alone. Just know
that an increase in bore diameter WILL help low and midlift flow when a 2.165"
valve is used.
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I don't mind that it's an unfair comparison; I'll probably be getting an iron block when (or if) my current engine goes, and was just wondering if spending a little extra on a block capable of 4.065 bore would be worth it. 8-10hp isn't worth it. 25-30 is.
#6
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Only true way to get an accurate comparison would be to use a flow bench using different test bores. Obviously, the larger bore will flow more even if the valves were not shrouded, but it should give you an accurate comparison given the correction factors that can be applied to the numbers on the flow bench.