New guy with a 70 Duster

Bill Dedman said
6. Locate an 8.25" rear axle housing, complete, from any '73-up V-eight "A" body car and bolt it in. You'll need new (bigger) U-bolts. She won't break it. The OEM 7.25" that comes in /6 cars is made out of toasted egg whites and will shatter at the first opportunity, with a 360 in front of it. Some early 318's also had that rear end (my '72 Valiant 318/904 did.)

BTW, the 8.25" rear is one that's bigger than the (7.25") rear end that's in your car, but still has a removeable plate on the backside, just larger and rounder... The larger, heavier, stronger, 8.75" rear end has a dropout center section (or, "third member") similar to a 9" Ford. That rear end would also work well in your car, but if you're not going to race it, the extra expense probably wouldn't be worth it.

7. A new drive shaft will probably have to be made, but since it will be shorter than the one that's in there right now, simply shortening that one might work okay.

Be careful. A lot of V8 cars, mine included, came with 7.25's from the factory. Look for a ROUND 10 bolt cover for an 8 1/4. I would, however, since you've got a Duster, suggest a 65-70 B-body 8 3/4 rearend with the spring perches moved inboard 1/2" per side for the stock shackles. I have the offset shackle kit, so mine looks a bit different for the spring location, but here's a picture:

I've had the 7.25 small bolt, an 8.25 large bolt, and this 68 B-body 8 3/4 in the car and this one fits the best by far.

If you do get an 8 1/4, I have the right driveshaft for it hanging in my garage that I need to get rid of.

Dual exhaust is a must. Very easy to do. I'm working on a custom side exit deal right now since my offset shackles won't allow me to get the pipes out the back anymore.