Despite all the differences, here's what you need to know: If you're driving an '87-93 5.0, you want the "sport
suspension" or "performance" rack, 15:1 ratio, 2.25 or 2.5 turns lock to lock. You do NOT want the 3 turns, 18:1 ratio rack. The only difference between the 2.25 and 2.5 racks is the thickness of the rack travel limiters installed at the inner ends of the tie rods, other than that they're identical. The 2.25 units were used in the 91-93 cars with 16-inch wheels.