cadillac to bbc

Could someone tell me if the older cadillac motors bolt into a chevy bb hole? are motor mounts and 400 trannys the same? Or are the trannys a different bolt pattern? I'm thinking about scrounging up an old Caddy motor.

 

Are you talking 425/472/500 series?

 

Cadillac use the BOP trans pattern (since '68, possibly earlier), however, the case is the only difference, so all the internals AND the tailshaft from your existing TH400 will slide into a BOP case and Bob's your uncle.
472/500s will fit into a BBC hole, but the exhausts end up a little wider, though shouldn't cause too much worry, if'n it's a truck your fittin' it into.
There is no known interchange between different motors as to mounts. All known motors use a different mount from any other, different, motor.
Cads are not BBCs, so the mounts are different.
Cads are not SBCs, so the mounts are different.
Cosmo