the later car did get a 8.8, the gt quad shock suspension came from the svo the control arms r from a lincoln con and r readily obtainable from the local junkyard 84 i think had 3.45:1 gears like stated above but very early cars dont have the quad shock setup so that would have to be welded on i have a 86 ford motorsport catalog her and it sells a quad shock kit part # m-4263-a might be discontinued though, and the later cars had 3.73:1
1.25 inches wider each side for a total of 2.5 inches go to mustangsvo.org and u can find more info and i belive a webring