Ron, it is actually 5" more wheelbase, (105 1/2 for the Fairmont, 100 1/2 Mustang), plus the Fairmonts have a bunch more rear overhang. I have had a couple of Fairmont street/strip cars with 302/T5/8.8 running gear, and when I used the factory mufflers and tailpipes from a 5.0 89 Mustang LX, I had the add 14" extensions on the tailpipes to get the ends past the rear bumper. So quite a bit more overhang.