I don't know what the kit is, but likely it's based on the '73-up OEM brakes. The OP's control arms are the '72 and earlier type with the sway bar tabs closer to the end. If he had the later control arms, sway bar and K-frame, there wouldn't be an interference issue with the bolt and nut. If you look at the earlier Kelsey-Hayes equipped cars with sway bars, you'll see shorter bolts and thinner nuts which clear the sway bar tab on the control arm.
