7 1/4 rear end hold up?
I wouldn't expect a 7-1/4 to last behind a stock 273. There is a pile of seven of the sorry things behind my garage with the pinions ripped out of the carrier. And, these were from the days when my 273 engines were basically stock. If you go around a corner and one wheel is on ice or snow and it spins a bit and then catches solid traction a 7-1/4 will rip it's guts out. Even minor hot rodding that causes one wheel spin will tear them up. I do have a sure grip 7-1/4 in one of my Barracudas that has held up to minor power modifications though.