Mainer,
The '53 -'54 block is cast differently where the water pump mounts; the '55-'62 block has a big round hole cast for the water pump impeller, right above the timing case, and the water pump shaft is several inches longer than the '54 engine.
Use of a '55 & later engine in a '54 & earlier truck requires either moving the radiator forward (requires some cutting of the radiator cradle) or use of a special "short-shaft" water pump, available from the specialty guys.
Have you priced a rebuild kit from Kanter Auto Supply in Boonton, NJ ?
The '54-'55 first series engine is somewhat rarer
than the later 235's; don't let somebody screw-up your block because they're not familiar with it.
