I havent figured this out, someone else might know, if you get covers that were for a mustang, the will bee too short. The bronco seat backs are couple of inches taller, the butt seat part fits fine.
the Toms front covers I got were too short, we had to put silver material at the bottom. Fought like hell to get them on-took several of us. I am not an upholstery person and my experience with these seats will ensure I never attempt it again. I took mine to a professional shop last week so they could finish/fix them . I should have started there.
My seats are the silver ones for a 66. Make sure you get the right ones, or go seek professional help or both. One of the most difficult things I tried to do.