Check out this link I found this morning on disk brake conversions for mopars
http://waywardgarage.com/135/brake-swaps-for-mopar-musclecars/I found the spindle section particularly interesting.
Spindle
The spindle to use when installing late-model breaks was introduced on 1973 B-body cars, and carried over on all later B- (Coronet, Satellite, Road Runner, Charger, GTX, R/T, Belvedere, Super Bee, Cordoba,’76-78 Fury,’77-78 Monaco and ‘78-79 Magnum), F-(’76-80 Volare, Aspen,Road Runner and R/T), J-(’80-83 Mirada and Cordoba), M- (’77-78 Diplomat, LaBaron, Caravelle and 5th Ave.) and R- (’79-81 New Yorker and St.Regis) bodies. Yes, even the transverse torsion bar cars used the same spindle. This spindle was designed to accept the post-’73 rotors, which incorporated a larger inner wheel bearing and seal.
The late model spindle retained the same steering arm/ball joint mount spacing specifications as the earlier B- and E- body spindle, and this is the key that makes late-model break swaps possible. It will bolt directly in place of the earlier spindle, and therefore allows the installation of any of the front disc setups found on the various post-’73 B-,F-, J-, M- and R- cars.
Unlike the ‘70-72 B-, and all E-body spindles, the late model spindle mounts the caliper to the rear of the rotor. This allows fitting disc breaks to the ‘66-69 B-bodies equipped with the factory front sway bar without interference problems.