Heads: 317s vs 243s

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Nov 6, 2009 | 10:32 PM

mad max motorsports

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From: Westland, MI

Heads: 317s vs 243s

My plan is to use 243 (LS6) heads on a turbo motor but have seen others and some one I know say the LQ4 (317) is just as good or better for boosted LS engine.

Any input to this?

Nov 6, 2009 | 10:39 PM

RS_SS69

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From: Denver, CO

317s have a larger combustion chamber at 72cc for lower compression, 243s have like I think 66cc so most go with the 317 to help aid compression. Nothing wrong with a 243 if your pistons are matched accordingly

Nov 6, 2009 | 11:01 PM

1SLwLS1

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for stock LS1 engine, 243s will bump compression to ~10.5:1, with 317s it is around ~9.0:1 with a .052 GM MLS head gasket

Nov 6, 2009 | 11:34 PM

mad max motorsports

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From: Westland, MI

Outside of chamber size/compression ratio what is the big difference?

Nov 7, 2009 | 12:34 AM

dudeman

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From: texas

i dont think there is a big difference. i think the ls6 heads out flow the 317s by a very small amount up top. when using a compression calculator i came up wiht 9.6:1 on a stock bottom end ls1.