[SCOTI]

Originally Posted by cjohnson6772

I will probably go 20s in the future but I thinking about trying to take a multi-step approach so I'm not changing everything all at once. I may be lost, but the clapper clearance changes with drop spindles? The truck already has factory discs and the wheels in question on factory spindles.

Caliper clearance changes w/the caliper used. Light Duty spindles vs HD spindles use different calipers & rotors. This is a common watch-out when purchasing aftermarket spindles. If the spindle is based off of the 73-87 year models, clarification of which spindle is required. CPP would likely state what specific app the spindle is for so you know what brakes they'll use.

Beyond that, backspacing of the front wheels is probably the No.1 issue for contact related problems. Your stated 15x8.5" w/) offset is roughly 4.75"BS which is crowding the a-arm @ only 15" OD & I would bet comes close or contacts the outer tie-rod end.

Larger OD wheels can pull that width/offset off because things will fit within the barrel better. Tubular arms can yield more clearance near the BJ pocket depending on how it's made (shaped). Better quality arms are usually clearanced by the manufacturer.