71 duster bolt pattern?
Read this:
http://www.moparaction.com/Tech/archive/disc-main.html
I have a complete set up from a 74 Duster for $325 + shipping
Easy swap.
Rears - you either have to drill your stock axles/drums or replace the backing plates/drums and axles with a BBP set up.
I also have a set of SBP disc/uppers off a 68 Cuda with good rotors. They came from a running driving car.