Big block / small block

Whats the difference in the bell housing area/crankshaft flywheel plate between the small block and the big block mopars ? Im having a hard time finding a 360 reasonably priced thats close, but there is a 413 wedge motor close to me, as well as a couple 440's. I plan to make an adapter to bolt it up to my 1960 dodge tranny......if possible. Id like to keep the old thing all mopar.....but if forced, I will have to stick a bowtie in there.....since they're easy to find.