While waiting on some new base gaskets I decided to re-install a cylinder & piston to measure the deck height without any base gasket. It turns out that with these pistons and my digital caliper, the caliper method was not very reliable/ repeatable, as I think that most of the time it was resting on the edge of the dome, rather than the flat piston edge, because the caliper depth rod is just too thick.

So I took the Stomski valve timing tool that I have and sat it on top of the cylinder, zeroed it on the cylinder, then slid the indicator point over to the piston edge nearest the piston pin and read .020” deck height with no gasket. So I’m already at .50mm. This method was repeatable and I got consistent measurements. If I stack a.50mm and a .25mm base gasket, I’ll be right at 9.8:1 CR.