Using 8 3/4 with /6

[Mopar92]

The Slant is a very temperamental little critter. It WILL see the difference in weight and rotating mass going to an 8.75.
Automatic trans? No Stick? Not spraying 150 horse at the hit? KEEP the 7.25!
3.23 and 3:55 were popular gear sets in early cars, as were Sure Grip units. A little hunting will get you hooked up with a killer 7.25 for less than an ABody 8.75 housing will cost. If you're on a real budget, weld up the spiders and have at it.
Spider gears aside, that rear is MUCH stronger than people give it credit for.

I would swap it out if I broke it. We punished a 7.25 sure grip 3.55 with a warm 318 4 speed. We never ever had any trouble out of it. It's a Dana 60 in a diaper.

 

[cosgig]

All of the parts to make this swap can be had, and if you're patient and keep an eye out, you can score great deals on what you need!! In the last 2 months I have found and purchased the same parts you need, including...

A complete A body 8 3/4" under a car I purchased, I swapped the car to a 7 1/4", kept the 8 3/4" and doubled my money selling the car......freebie!!

Dr Diff setup 741 case, 3:73 Auburn SG ( not the cone style), all brand new...$400

Yukon LBP A body length axles with green bearing setup, all like new...$150

I have brakes to go on it, so I have $550 invested so far, and if I sell the center and sbp axles and brakes from the housing, that number will be under $500!

Deals are out there, you just have to be patient, and have a keen eye!!