B- body 8 1/4

I dont think the 8.25 ever made it into any 1970 Mopar.I thought the first year was 73?
So measure the center to center of the spring perches.IIRC A-bodies were 43.5, Bs were plus about 1 inch.
Seems to me the A-bodies with the bent T-bars, 76up, had a plus 1inch rear track. The perches IDK.
That would make the tracks nearly the same, on those two.
As to the guts, cant say.