70 duster from disc brake swap

Hi guys, I know this question has probably been on here many times but I'm new here and this is my first a body. I have a 70 duster with front drum brakes and I'm going to upgrade to front disc brakes. I bought a set of upper contr arms off a 71 with disc brakes. Will those work ? I have 2 sets of disc brake spindles. One off a 85 diplomat and the other are off a later model charger. Which would be better to use? Also, what front end rebuild kit do I buy? Do I need problem solver upper control arm bushings? I know I need a new proportioning valve and that is no problem. I also plan on keeping the 7&1/4 rear around for a while. Is there anyway to upgrade to the big bolt pattern? The engine is going to remain the stock slant six for a long time so in not worrying about tearing it up. Thanks for the help.