I'm not sure on the cragars. I'm running the 14x8 slotted Indy mags with big bolt pattern disc and the only problem I've run into is you have to be careful where the stick on weights are on the inside.
I'm gonna go out on a limb and say No. Sliding Calipers on 76 Duster would be BBP, and I believe you have to go up to a 15" rim.(correct me if I'm wrong) or am I just thinking about the 11.75" rotors???
Most aluminum mags have thicker rims than steel wheels -- those are the ones you have to look out for. Cragars have steel rims and cast centers, so they are probably OK. Rally wheels are OK. 14" American Racing TorqueThrusts won't fit over disks.
And now the correct answer. Factory calipers depends on the wheels you are using, plain and simple.
My conversion, stock 73/4 Duster type calipers, ET unilug 14 x 7? "barely" ticked, I ground 1/8" ? off the tops of the calipers. This could also have been solved with something like Summit 1/8" thick spacers
My old sixpack car, had factory optional single piston pin type calipers and U.S. Indy 14" on front. Cleared OK, "back then" that was a long time ago, so I don't know by how much
EITHER of these cars could be used with factory style 14" steelies