How did he mount the generator? Front-mount distributor engine generators are on the RH side, side mount distributor engine have a generator mounting area added to the LEFT HAND side.
That is the difference in the BLOCK. The other differences are camshaft and front timing cover, and, of course, distributor.
So, if you have a side-mount now, on your front mount block, swapping a true side-mount block in it's place should present NO problems.