I don't know anything about the Caddy motor, although I'd venture to guess the tranny is a TH400 which should be plenty strong enough for most applications.
The rear end...well, let's just say that there were several types of rear ends used in Novas. they range from 8.2 inch 4-lug setups in 62-63, 8.2 5-lug, 10-bolt used thru 72 or so 8.5 inch 10 bolts used in 66-79 applications and a smattering of 12-bolt units here and there.
So by saying a "Nova rear end" you've essentially said, "I have a rear end that may have come out of some GM car." I'd suggest finding out a whole lot more about it here:
NovaResource.com before going a whole lot further.
