Disc brake conversion 64 Dart GT
a bit of grinding also had to be done with my original parts
i fitted new old stock brackets and slider calipers to mine, i lucked out on an australian job lot, and the brackets needed grinding because they rubbed the rotors and that's all OEM kit for my model of car, with standard 2 piece Hub/rotors, and good wheel bearings, properly adjusted.
sometimes you just get a tolerance stack up. presume the brackets were sold NOS because they were recognised as rubbing. i.e a bit rough cast and too fat in 1 area, at some point in their 50 year life :)
they cleaned up nice i took the slight webbing out of the 90* angles and a bit off the face below the slider head and all was well.
if i have to do it with factory parts i can easily understand the odd issue with aftermarket