leaded or unleaded fuel

dartlove said
Dome piston +6.5 comes out of the hole at the flat .023" . .060" mls gasket. 4.310 bore 4.250 stroke 70cc heads

You have no idea what the dome volume of the piston is unless you do a downfill and measure it. Otherwise it’s a guess, and probably a poor one.

Can’t count how many engines came through the shop that the owner said has XX.XX compression ratio and 99% of them were a point or more off.