To answer your original question, yes, disk brakes usually move the tire / wheels out some. Some kits more than others. On that note, most of the kits replace the 6 lug wheels with five, 4 3/4 - 5, so your wheel issue may change anyway. There probably are kits with six lug hubs, but I haven't looked. My '37 truck has a newer front axle, early '50s maybe, it has a kit from MasterPower Brake, installed in 1999, uses '70's Camaro/Firebird rotors and calipers. The newer kits are using the later model metric rotors and calipers. What you want is a kit that uses common, easy to get replacement parts. Mine has all standard parts except the caliper bracket which is custom made for the application.
