The stock rims may or may not interfere with the disc brake caliper. Sometimes they are very close and a small bit of grinding on the caliper casting will allow them to clear. It depends on the size and offset of the stock wheels. Others insert spacers between the rotor hub and the wheel, but I don’t recommend this method as the wheel studs may not provide enough thread engagement for the lug nuts. The interference area is normally the tapered portion on the backside of the rim as indicated below:
[IMG]http://img836.imageshack.us/img836/2590/wheeldrumbrake.jpg[/IMG]And here’s a comparison to the profile of a disc brake wheel:
[IMG]http://img196.imageshack.us/img196/6461/wheeldiscbrake.jpg[/IMG]If your desire is to retain the stock appearance and original hubcaps, this can easily be achieved by using 1973-1987 4x4 6 lug stock steel disc brake wheels. Although they have 4 hub cap bumps instead of 3, the original hubcaps will fit just fine. The wheels look slightly different, but with hubcaps in place the change is almost undetectable to the casual observer. You also gain the advantage of having safety beads in the disc brake rims which help keep the tire attached to the rim in case of a flat.
Here is a picture of a 15x6 on the front of my 1960 GMC when it still had drum brakes:
[IMG]http://img835.imageshack.us/img835/234/drumwheel.jpg[/IMG]And here’s a shot of the rear 15x8” wheels wearing a 54 Chevy passenger car hubcap, indicating any standard 10 1/8” hubcap will work:
[IMG]http://img40.imageshack.us/img40/8357/drumwheel02.jpg[/IMG]