I bought a trailer load of parts a couple years ago with an engine with a replacement block. 1921 cast date no serial #. It showed mininal wear, std crank miked perfect, cast Ford script std pistons in hardly worn bores. Only thing is, the center main cap and the front cap are exactly the same! I put it all together after a refreshening, new field coil, recharghed magnets, rings, and refit the bearings. I've ran it now for a while but not too far. I have too short a center main cap, since it's a front main cap, what could happen because of this? I'm thinking I need to replace it and should've asked this question a long time ago. Were replacement blocks supplied as just blocks or as complete assemblies or both? Could this be a factory mistake or a shade tree fix? Everything seemed to be almost perfect with little wear and it runs like a top.
Either way Corey. It is hard telling who did it, but there in only about .050 thousandths difference, with out going to measure one. I don't think it will make any difference to the longevity of your engine. The rear main normally wears the worst any way, becacse of the weight of the Transmission. Herm.