Here is a view of the "CONE LOCKING" style rear axel guts. This is a 7.5 inch rear end form the factory. These werent very strong though. The 8.8 inch rear axel was the stonger mustang axel and was introduced in 1987 in the mustang. They will bolt right in as well. I plan to install an 8.8 with 3:55 gears in my car in order to preserve my 7.5 inch 3:45 axel.(which is still in good shape)