The BEST and easiest way is to find an '87 or '88 Turbo Coupe Thunderbird.They all have 8.8 disc rears with traction Lock.The manual tranny cars have 3.55 gears,and the automatic cars have 3.73 gears.If you were near me,I have an extra 8.8 with 3.55's in the garage.The mark VII rear probably has 3.08 gears,and,it'll be one inch wider on both sides.If you go with the disc rear from a Lincoln mark VII or T-Bird,you'll also need to grab the parking brake cables and you'll need to upgrade your master cylinder.One for a '93 Cobra is great.Good luck.