Reading up on it all is getting me closer, but I have to throw another wrench into the works.
How does all this info and modifications translate into a 72 Demon?
It’s pretty much all the same. In the back a ‘72 Demon is no different for body clearances or frame dimensions than a ‘70-76 Duster or Dart Sport. Obviously the rear axle options changed from the factory, but we’re talking about axle swaps too so that’s less relevant.
There are some minor differences in front fender clearance because of the different shaped openings, but, I ran the exact same wheel/tire combo with ‘74 Duster fenders and ‘71 Dart fenders in the front after I changed over to make my car a Demon clone.