73 Dart Rear End Swap

But wouldn't putting a b-body rear in as is limit tire width? Right now the max I can fit is about 245s in the rear, would like ateast that or even a bit wider with the new rear end.

And I was looking Into 8.25 swaps but I'm having trouble finding them near me, I can easily get a Dakota 8.25 but that's a bit different.

Would an a body 8.75 fit in if the spring seats are moved in a bit? And just run a different offset tire to fit?

8.25s are very plentiful. Just gotta know where to look. Most junkyards will have a couple. Heck watch the classifieds here, you may just find one near you in there.