My truck had 235/75/15s on all 4 corners. When I lowered it, I upgraded to new style tie rod ends and used a drop axle from Nostalgia Sid's. With the wheel mounting location effectively moved up 3 inches in relation to all the other components in the front end, and the new style tie rod ends being a little bit bigger than the factory 1950 style, I discovered I had interference between the sidewall and tie rod end. I went with a narrower tire and ground the casting seam off the driver's side tie rod end to make clearance.
I don't know if you have anything else going on besides disc brakes, but that would be another place to check.
I am running those same wheels, but 15"x6", on mine with the CPP kit.
