How universal is the 7-1/4" axle

I ran a 7.25 behind a 340, once,around 1975 it was.It was in a 65 valiant wagon.I guess they were stronger back then.lol.In an A-body with skinny tires, and a slanty, mines pushing a half a million kilometers.more than a quarter million miles.POW!
So if you need to stick to that rear, no problem. I think if you stay in the same family you will be ok. The familys are; 1)early A, up to 66,and 2) intermediate As, 67 to 72, and 3)late As, 73 up. Groups 1 and 2 are sbp. group 3 are mostly large bp. In Canada 73 was a crossover year with slantys IIRC getting the sbps.
BTW whats wrong with your one axle?