I have a 75 Duster with the small bolt pattern, drum brakes. Want to convert to the large bolt pattern disc brakes. Will brakes from a Volare' / Aspen work?

Also what all year Darts/Demons/dusters will work?

Heres how I remember it.

I believe the F body (Aspen/Volare) question will get you different answers as I think that was the heated debate between two popular mopar Tech editors. The suspension angles and geometry during suspension travel were the issue. Folks have done it.

The 73 and up A bodies Dart Dart sport Duster and Valiant will all be good donors.
(E bodies will also work, unsure if the upper A arm swaps over)
The upper ball joints are larger in the 73 and up cars with larger brakes. If you have the small pattern than I think you still have the small ball joint? If so the upper A arm is needed

Your '75 already has big ball joint UCAs.

Any 73+ A-body donor w/discs will have what you need. Rotors and calipers are still available at the parts store.

Basically, all you need from the donor is the proportioning valve, spindles, caliper brackets, & dust shields...and new wheels. You'll also need to make some decisions about your rear bolt pattern unless you want to carry around two spares.

Personally, I'd pick up the donor UCAs to resell, so I could recoup some of my expenditure.

The 11.75 rotors will slide right on there and then you can use brackets from Mancini racing to hang some Viper calipers on there. Bolt on deal.