I read somewhere that early MELs ('58-'59 and maybe '60?) shared the same bell housing bolt circle as the FE engine series. The later MELs used a 'partial' FE pattern. Does anyone know how 'partial'? I'd like to run a toploader behind my '65 430 but if it's not plausible ($$$) to add mounts to it, then I need to start looking for a '58-'59!!

Welcome mrevildoer. I think the 58-59 MEL bell housing pattern is compatible with the FE pattern. I heard that the 1966 and up 462 MEL Block features a dual bell housing pattern.
I don't know how partial the 65 block fits.

Thanks. I need to find another block anyways, so I suppose I'll have to narrow my search to a pre-60.

See
http://www.ford-mel-engine.com/viewtopic.php?f=3&t=445