Not that I would use ford parts on my dart but has anyone measured a mustang rear end compared to an A body? 5.0 mustangs are everywhere at the local pull a part, have the 5 on 4.5 bolt pattern, and are pretty stout. Just a thought.

66-72 A-body rear ends are 57 1/8 inches from drum to drum and 43 inches center to center on the spring perches. I've seen several guys put Ford 9 inch rears in A-bodies before. I don't know why, other than they're cheaper and readily available. They certainly aren't any stronger than an 8 3/4. Even the looked down upon 741 case has a bigger pinion shaft than a 9 inch Ford. Although, I think the later Mustangs have an 8.8 in them?

Mustang 8.8 rears are 4 link, coil sprung. Which means you need to put leaf spring perches on them.

As for width, I am sure someone on the internet measured on once and posted the numbers somewhere.

http://www.hotrod.com/articles/ford-8-8-rear-end/

I was barely OK with using type F in my trans & the chebby HEI module I had to hide it under the dist housing!