boring 64 430

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JimV57
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boring 64 430

Post by JimV57 » Wed 16. Feb 2011, 03:50

I saw the thread on the earlier 430 bore, but I was curious about the combustion chambers as they are in the block on the 430. Would a bore of .060 change the combustion chamber dymanics at all? I'm assuming it would change the compression ratio since the combustion chamber would be smaller - or would the combustion chamber have to be milled as well?

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Theo
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Re: boring 64 430

Post by Theo » Wed 16. Feb 2011, 04:23

No. Don't worry. Oversize pistons come destroked out of the box. The manufacturer build them w. slight changes in either the dome, valve pocket or piston height (Pin to top of piston lenght) in order to compensate for what you mentioned.
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Re: boring 64 430

Post by 430 6V » Thu 17. Feb 2011, 10:12

I agree don't worry.

Given the same piston dimensions except bore, the compression increase will only be slight due to the increase in combustion chamber size from the overbore.

A .060" overbore can wipe out the cylinder depression located on the plug side, but it does not need to go back in. Haven't done an A-B comparison but power can be made without it.

FYI: The MEL engines I've measured have been well under advertised.

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