David Vizard, Uncle Tony's garage, Unity motorsport. Mission impossible Dodge 302 Head porting

Mattax said

It will be worth knowing.
With the variation in factory castings, we can only ballpark the compression ratio.
Even with everything else stock, it would be good to know how much its been changed, or at least where its actually at now.
Actually since its before assembly, there's time to consider head gasket thickness.

Click to expand...

OK
The head gaskets are the .028 ths Mr. Gaskets.

And the Factory 9.2:1 valve relief flat top pistons (std.) sit .040 down in the hole.

I know cause I measured them. The 1969 318 block was not decked, untouched .

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With everything figured in on that '69 318 build, we figured came out to 9.5:1, Pistons, 302 closed chamber heads, and the thin head gaskets.

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That was also figuring a little deduction for the valve reliefs in the pistons too.

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OK, Brian just now got back to me with his cr calculations.

59cc 302 chambers



Brian's Quote:

"I have numbers he will need to be accurate. My calculation is 9.6:1."