Stop using the web. 318 heads unmilled are 68 cc per chamber. 72 cc chambers are 340/360 heads. They usually only lock a thread if someone takes the discussion off the rails.
Well, I used Wallace racing, with .080 down and a .032 compressed gasket, using 68cc, 8.24:1
I used 64cc heads, 8.51:1.
So I suspect the closed chambered heads must be 62 cc, and that may be where the 8.6:1 number was for?
.080 below deck at TDC holds with my engine, it’s .030 over, and .095-.105 below deck, I attribute the difference to common rebuild pistons that have .020 lower compression height.
I’m unsure what a normal CH head gasket was on a 318 new, I’d think .039?, but .032 was the smallest I could find except for a marine HG at .015.