The X2 balljoint fits 94-03 Mustangs. It also fits 87-93 Mustangs that are equipped with the Ford Racing M-2300-K Cobra Brake conversion kit or Baer 13" or 12 " American Sedan Brake kits. It will not work with stock 87-93 brakes
because of interference between the rotor and the repositioned control arm.
From the Steeda website.
Hope this helps.