I think this is prolly the best idea. I believe unless you get into the shortblock, even a head swap to the car stuff will still leave you with a low compression truck engine. I vaguely remember some of the industrial engines having a crank that stuck out farther than a passenger car crank, in addition to the 8 bolt flange. Could you put a straight edge across the back of the block, and measure to the flange so we could compare?
