Chrysler 8 1/4

I'm almost afraid to ask! If a Jeep Cherokee has a 8 1/4 Chrysler rear-end, what would the possibilities of it fitting in a 68 a-body? The fella selling it says it has a Dana 35 w/3.55 gear. Also. the flange-to-flange measurement is real close to my b'cuda. The b'cuda measures in at approx. 54". I read somewhere on here the a-body 7 1/4 was 51" F-to-F.
I put together a document of what I could find about sbp to bbp swaps. Here is a summary of what I came up with.

"A body 8 ¾ - 52 5/8" flange to flange. 43" center to center on the perches.

A-body, 65-72 55.6 43.0 4" lug bolt circle, offered in heavy duty apps.

The only true bolt in is a 7.25 LBP unit.

So choices are:

1. 8 3/4 B-Body rear - Have to cut driveshaft. 1.5” difference

2. 8 3/4 A-Body rear - Cut driveshaft.

3. 8 1/4 BBP Rear - Cut driveshaft

4. Keep 7 1/4 rear - Run adapters or redrill axles/drums. Keep driveshaft.

5. Find a later 7 1/4 with the big bolt pattern. Keep driveshaft.

6. Get a 73 up bbp a-body rear. I have seen 7 1/4 and 8 1/4 priced reasonable."

Why can't you swap axles from 73-up 7 1/4 bbp to an early 7 1/4 sbp, if all that you are attempting to do is migrate to a 4.5" bolt pattern.

I'm confused
Jim