Theoretical H/C question

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Oct 23, 2009 | 03:11 PM

Gatsby

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From: Baltimore, MD

Theoretical H/C question

I was just wondering, if one were to put a set of ported ls6 heads on a 346 and it gained say, 40HP, then you swapped the same heads onto a 402, would they gain more than 40HP over the stock ls2 heads?

What I'm asking is, do heads react better to bigger cube motors? If i were to go from 346 would the heads make a bigger difference?

I hope this is clear.

Thanks.

Oct 23, 2009 | 03:23 PM

1SLwLS1

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that depends on many things, such as runner size, as well as the which heads were being compared to. As a rule of thumb, you increase the displacement, you increase the runner size proportionally, but just as much success could be had with small runners.

Typically there is a balance between intake velocity as well as flow. Sure you can make a head that flows all out, but that also decreases velocity, so there is a fine line to be had.

Oct 23, 2009 | 05:12 PM

Gatsby

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From: Baltimore, MD

When you see 205 vs 215 vs 225 etc, is that runner size? I see that on a 346 people are having the best luck on 205's, would it be safe to say that a 402/416 would benefit from a 215?

Does a runner size too big for a particular motor hurt performance everywhere or just down low?

Thanks for clearing this up, i did search, but the information is unclear.

Oct 23, 2009 | 05:43 PM

PREDATOR-Z

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From: BFE

Theorecticaly, Yes

Oct 23, 2009 | 06:30 PM

ss454327

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From: Scott, AR

I wouldn't think you would gain the same honestly. Maybe if you were swapping from the same head to the new head but I think the LS2 had LS6 heads and they flow a lot better than the LS1 heads.

Oct 23, 2009 | 07:13 PM

livefast1

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From: easton, md

is would gain more also depending on bore size, if you swapped the heads onto an engine with a bigger bore you would be unshrouding the valves which should show more gains.