How to tell a 7.5 from a 8.8 rear

The rear on the left is a stock 7.5 rear end from a 85 Mustang GT. The one on the right is a stock 8.8 rear end from a 87 Mustang GT. Notice the differences between the two. The 8.8 is more a rounded square where the 7.5 is more oval shaped as seen by the rear cover on each model. Also the 8.8 bolts have more of that ARP look to them instead of the stock grade 8 bolt look.

Here are front shots of each rear. (7.5 on left and 8.8 on right) Notice the suttle differences between the two. The 8.8 is easlily picked out by the site plug near the yolk area of the rear. The 7.5 does not have this site plug. Other differences are the shape of the housing itself and the large S cast into the 7.5 housing.