A friend of mine just bought a 05 Mustang King Cobra (a project car from a custom shop out of Orlando), I haven't seen it in person so I dont know much about the car. He said it isn't supercharged, so that makes it a GT with a dress up kit, right? But mainly it needs a rearend. Is the rear axel in a GT and Cobra the same? Also, whats the size and gear?

 

The stock Mustang GT rear end is the Ford 8.8. Its been around for years. Many gear choices for it 3.55, 3.73, 4.10, etc, etc.