340 Head gasket
I bored my 340 .020 over, KB pistons, Eddy 60179 Heads with the Felpro .039 Compressed head gaskets. Cranking compression 165 ish. I'd have to check my notes. I'm just wondering how mush compression would bump to with the .028 gasket.
You'll get about 1.8 psi for each degree of Cam advance. and/or
same 1.8psi per an increase of 1/10 of a compression point.
Swapping from 039s to 028s at same 4.18 bore is worth about 3/10s compression ratio, and 7psi.
A custom 020 gasket with a 4.07 hole, will get you 4.5cc, less than the 039s, increasing the compression ratio of a 10/1 engine to 10.55, and the pressure jumps from 166 to 177, a gain of 11psi.
-----------------------------
With alloy heads, long rods and short stroke, I bet you could run near 200 psi and still on 87E10.
I mean, with the closed chamber eddies, I ran 195 with a 360 on 87E10.
Since 2004 tho, I've been at 185 or so on same 87E10.
she's got well over 100,000miles on 87E10. and went 93 in the Eighth on that swill.
I run the 039FelPros, with the pistons up ~.007 for a Q around .032. I have run the Q down to 028 without contact.