How universal is the 7-1/4" axle

I ran a SG 7.25 behind a '65 A w/340 for most of my senior year in high school. Burn outs and all. I would probably still be rocking it if :I didnt do a neutral drop backing out of a driveway with 10 inch tires, BANG! and IF I didnt sell it with a replacement 2.76 one legger to a dude a week before I shipped out to boot camp. I think the SG's were much stronger than the peg legs, guess it didnt matter as the guy wrapped it around a cement light pole 3 months later. Dad sent me the newspaper clip, OUCH!