ID Rear End Help

[Boedighw]

Guys,

Good evening, working on a '72 Duster. Needing to know if I need to upgrade the rear end. The car is in storage right now but snapped a picture of the center section. So what rear end is this?

I'm struggling because there is some sort of adapter or spacer that is pushing the wheel out causing it to rub when I go over bumps. Is the spacer to look cool? Or is it an adapter since they did a large bolt pattern disc swap on the front? I believe all 8 1/4 were large bolt pattern so why the aluminum something's on the wheel?

Thanks for your help!

 

[Kern Dog]

That does look like the 73-76 8 1/4 axle. It is a very good axle and worth keeping in place. The spacers that you mention may be there as you mentioned, just to move the tire out wider for a more aggressive stance. Most Duster/Demon/Dart Sport cars look funny to me when fitted with stock tires and wheels. These cars are wider at the rear wheelwell than the same year Dart or Valiant even though they use the same rear axle. The car has a long body overhang at the tire like a 68-70 Charger with stock tires.
I have put 68-70 B body 8 3/4" rear axles in many Dusters. These axles are 3" wider than the stock and help the car look better even with a 7" wheel. Here is one example of a moderate sized tire on a Duster with a 68 Coronet axle:

 

[RustyRatRod]

That's an 8.25.

 

[Boedighw]

Not caring about original or trends does it make sense to keep this over a 8 3/4 swap? Planning a 440 build that will be about 400hp ish (essentially magnum with new style cam, intake, headers)

 

[Kern Dog]

I'd look for a 68-70 B body 8 3/4" axle. The 8 1/4" is tough enough for the small blocks and even mild big blocks. Anything that will see some hammer time will benefit from a more durable axle. Also, chances are this axle is a one legger. Why add Sure Grip to an axle that was never put behind a 440 anyway?

 

[Kern Dog]

Where in Oregon are you? Anywhere near Sandy? Wildcat auto wrecking surely has a few of those B body axles in stock.

 

[Leadfoot]

does it make sense to keep this over a 8 3/4 swap?

You're not going to hurt that thing. There's a lot of variables like converter, gears, tires, and weight but those things are a lot tougher than people give them credit for being.

 

[RustyRatRod]

Not caring about original or trends does it make sense to keep this over a 8 3/4 swap? Planning a 440 build that will be about 400hp ish (essentially magnum with new style cam, intake, headers)

The 8.25 will be just fine.