Is an 8.25 rear with 2.74 gears upgradable to better gears?

Hello,
I was wondering if an 8 1/4 rear end with 2.74 gears is upgradable to say 3.55-3.91's? I heard that some of the rears with lower(numbered) gears are different than the higher (numbered) gears,the housing and carrier was different, but I dont know what the cutoff is. Thanks. Looking into rears for my 72 Duster and want to get something that I can put better gears in.

Butch
Author: admin