Smoothie wheel for disc brake

[MASTERBrian]

I'm looking at summit racing US Wheel steel 15x8 series 51 smoothie wheel. I called us wheel and they said no, won't work with my 1960 with disc brakes. They gave me measurement of 7.5" from beed to center. I called CPP they said Measure top of caliper to center of dust cap. I seem to get 6-3/4". CPP also says to ask if they'll got 71 C10. I call US Wheel back and they say yes 71 C10 with drum, my understanding is 71 was all disc, maybe not, so I ask again and he says if stock 71 C10 they'll work. I call summit, they get some info and say they should work on 71 c10 with disc.

Anyone know?