[dscott]

If the Mustang II suspension is using the strut type lower arm then you may be rubbing on the strut. If the tires in the front are pretty wide and the rack is not centered properly from lock to lock then you can have a problem on one side. This is usually noticed by looking at the tie rod ends. If one is screwed out further than the other by a good margin then you may be hitting the lock on one side and not the other, causing the tire rub. If this is the case then the strut will be nice and paint free on that side.
Don