will this run on pump gas ?

Adam. Your going to need to know exactly where the piston sits in the block. I have has 2 engines with the KB-107's and they both came in at different spots. 1@ zero, 1@ .010
Moped has told me that most (if not all IIRC) of his 107's were below deck on stock blocks.

Of course you all ready mentioned thicker head gaskets and opening the head up. InJUST start on the short block set up and the. From there, we can see exactly what you got. Unless you have a machinist blue print it all out. Block, crank, rods.