46gmcpu -
I have not had the wheels off yet, but visually they are not deep set that would indicate a lot of backspacing to me. Please take a look at the photos if you can.

The wheels are newer aftermarket chrome wheels - Ion I believe is what the center cap says...

Longbox 55 -
You are correct, there is a slight deviation from center to lock on each side. Turning right, where the rub is, I can rotate the wheel about 2 turns. The contact with the pitman arm hits at 1 rotation of the wheel.. That leaves the left turn with about 1-1/4 wheel rotations to lock.

How is best to compensate for the lock to lock difference. I have seen a "dropped pitman arm" for sale to adjust for a lift kit.