Compression Ratio Blues
#1
Compression Ratio Blues
Will my '83 4x4 C6 auto truck perform well with its 302 creating 7.9:1 CR? The 302 is bored .040 over with...72cc combustion chambers (ported and polished - Except intake runners. Stock cast headers and manifold with a Motorcraft 2150. Truck will mainly see mild street, moderate towing and occasional moderate trail use.
I'm considering domed top pistons to boost the CR. The stock combustion chambers averaged 68cc before the P&P.
Some good advise would be appreciated.
I'm considering domed top pistons to boost the CR. The stock combustion chambers averaged 68cc before the P&P.
Some good advise would be appreciated.
#2
Join Date: Jun 2006
Location: Ottawa, Ontario
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It'll run but more compression would be better, consider chalking this up as a learning experience and go find a set of E7, F1, F3 heads to bolt on. All of these would boost static CR at least a full point from what you have now an the F1 and F3 heads could out perform your port job without being touched.
#3
#5
You can always mill the GT40's for more compression, but before doing so, cc them first. The Mustang 5.0 GT40's were milled a second pass to get their chambers to 60ccs at the factory. If they check out at 64 cc's, then you can mill them .040 without running into intake fitment issues. What cam are you running ?
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