disc brake setups...front/rear

I am needing to get the parts ordered for my 70 Duster project. I bought an 8 3/4 that I need to convert to LBP and I would like to update to disc brakes. I am wanting to find a kit that has cross drilled and/or slotted rotors that will clear a 15" wheel (Weld Pro Star or Billet Specialties Street Lites). Also I would like to find the matching front setup. I have seen kits that use the Viper caliper but will those clear a 15" wheel or do you have to run 17" wheels??