I'm running a beefed up 7.5" rear out of a 82 regal I had. it has high strength Moser axles, 3.73 posi, and a rear end cover, with integral bracing for the carrier bearing caps
here's a pic of the engine sitting in it, just a typical mild mannered 550 hp engine (heater box will fit, am getting a different one, to replace the one I broke,be careful when sitting engine in)
and a pic of what the car looks like (taken before engine put in)
best part of putting a big block in one of these, no one will ever suspect it
also note: you will need the frame pads (that bolt to the crossmember)for a Buick 455. when you find a good candidate, grab these frame pads with it. best years of 455 Buick are 1970- 1974
you may have to move the engine till you get it where you want it, then drill holes, and bolt 'er in
I can take other pics of my conversion if you want
Buick 455 headers will fit this swap also