if having an alignment done, ask them to center the steering wheel and then align it.
otherwise, in the old days, i used to pull the wheel and straighten it. i think the stang has some sort of flat face cam on one side of the wheel splines, so it can only go back on in one direction (not sure on that, but the little voice upstairs is telling me that). so that would make that idea not work (other wheels i did this on were circular with uniform splines).
good luck.