[martindc1]

Depends on what gears you have. I'm guessing you have an HO52 rear with 4.57 gears. These have a removable "pig" which means the center section holding the pinion gear and differential unbolts from the housing. You could try to find a 4.10 pig, then you'd just have to change your front axle gears.

Another option, as stated above, would be to find a matching set of 4.10 or 3.73 axles from a later truck. Honestly, this is probably your least expensive option. However, there you may have to get the master cylinder from the later truck as well since you would be changing over to the later disk brakes.