8 1/4 or 8 3/4 rear end in my Duster 340?

Cafe are you saying the 8 1/4 in '73 was somewhat heavy duty? What size rear end would a '73 slant six have come with and as far as the disc brakes my car has them but I don't know anything about a big bolt set up. Demon seed I agree would you that in '73 not only was it not a "heavy weight application" but it wasn't really a high horsepower application either.