Upgrading stock 1971 318 heads

.045 cut?
I thought you said .040....oops I missed it
Between that and the .030 o/s we need some new numbers.
My math says a swept of 662.32 now, and
total chamber volume of (64-5.2)+8.8+19.98+5= 92.58, and
that makes a
Static compression ratio of 8.15:1.:)
Effective stroke is 2.86 inches.
Your dynamic compression ratio is 7.17:1 .:(
Your dynamic cranking pressure is 138.54 PSI.
V/P (Volume to Pressure Index) is 116
And the improvement is 116/105= Plus 10.5%

Now, advance the cam to 108 for an ICA of 48* and
Static compression ratio of 8.15:1.
Effective stroke is 2.89 inches.
Your dynamic compression ratio is 7.23:1 .
Your dynamic cranking pressure is 140.07 PSI.

V/P (Volume to Pressure Index) is 118:thumbsup:
now 118/105=plus 12.3% !

Or maybe you're there already. The compression test will give you a pretty good idea