Some 340 Questions

I've been away from these cars for so long that I seem quite naive! My origianl Barracuda was a 65, 273 bored .060, heads ported, full race cam, and I did race it, 12 flats on pump gas. had a 9" rear with 4.11's.

Now, for my NEXT question, how do I know zactly which rear end is in this beast?? Casting numbers, measurements, any help would be appreciated.

FF