You will get an overwhelming response for Ford Racing (FRRP) gears. That's what you want. You can pick them up all over. Just get a stang magazine and shop around. The gears should cost around $180. If you only have a couple of thousand or less miles on the car you won't need an install kit which is around $80 or so. Once the gears are installed the speedo can be corrected by the dealer or a Predator, Excal 2. Figure on paying $200-$300 for the install.