Thanks Sheldon, I'll try tracking some of those plates down.

I was slightly off with the figures above but here are all the measurements as recorded from my block, piston & head combo -

My head volume is 165cc

my dome is 109cc

bore 4.310"

stroke 4.150"

With a head gasket of .040" I get 16:1 compression

A head gasket of .157" would give me 11.5:1 which I think would be pushing things with our gas

My 1.000" down fill volume was 130cc taken off 239cc (the volume of 1.000" x 4.310" dia) = 109cc dome

I'm not sure how much the block has been decked or how much has been machined off the heads but the pistons do come up .958" above the deck.