New engine issues

PRH said
Btw..... the math doesn’t add up here.....

318+.030, zero deck, pistons with no dish or valve pockets, std composition gasket...... the heads would have to be about 73cc’s for that to only be “9:1”.

Did anyone cc a head?
What casting number are they?

Did you verify that the pushrods you swapped in were the same length as what you took out?
Click to expand...
The initial post says 'aftermarket flat-top pistons', but did not say that they are zero decked. So I suspect they are something like stock replacement 285's or 814's, which are down in the hole by .070-075". Now the 120 psi compression readings make more sense....