8 3/4 pinion angle
I've put a (Cop) Diplomat under a "Duster". Even with 15 cop rims it works. I added a spring to stiffen it up and prevent any chance of hitting bumps with a load and rubbing.
I cut the perches off and moved them. Had to weld a washer in the larger Diplomat perch hole. Used the car as a jig. Tacked the perches for the angle. Took it out and welded it. Remember the 8 1/4 has larger tubes so the 7 1/4 perches won't work.
Use the Diplomat brake cables. Works fine.
And shorten the Dip drive shaft.
I can't say about a Swinger. Would be too tight I would imagine.