Drivetrain advice for engine swap

In the original post, there was no mention of the wheel bolt circle 5 on 4" vs. 4.5".

If I recall all of the 8 1/4" are 4.5" Most (if not all?) of the a-body 8 3/4" were 4".

I would consider bolt circle diameter as another parameter when considering cost between of potential donor rears. Especially if you have to buy new axles with the 4.5" for the 8 3/4"

In my build, I'm switching to 4.5" all the way around. I am starting with the 8 1/4". I plan on upgrading to a narrowed 8 3/4" once I widen my wheel wells and move my spring inboard.