Thread: 6x-4's or 8s?
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Old 10-14-2021, 07:16 PM
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So if you go .030” over to a bore of 4.150” and then to the 4.250” crank, when you use the -4 head at 91 CCs , then by my math using common numbers for deck height, head gasket volume and valve notch volume I come up with a compression of 9.39 to 1.

If you run the -8 head at 98 CCs then your at 8.88 to 1 in compression.

With that 4.250” stroke crank every 3 CC change will change the compression ratio by 1/4 point basically.

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