[Rory McNeil]

After I stopped racing my 85 Mustang in Stock, I installed a 331 SBF in the car, which was otherwise still as it was run as a Stocker. Still had the full stock interior, and weighed the same (3100 pounds), with the same 4 speed Jerico setup. As a Stocker, I ran 4.88 and 5.13 "street" gears in the 8.8" rear, with 9 x 29 1/2" slicks. Typically launched at 62-6400 RPM, with the 331, it ran a best of 10.15 @130 MPH, with mid 1.3 60 foot times, and with the same 4.88s that were in the car when it was a Stocker, I ran it 2 seasons with the 331, after about 5 years with the Stock Combo. Never hurt a ring and pinion with the Motive 4.88s. However, as a Stocker, I broke 2 sets of 5.13s, only running low 12s at 107 MPH, at low 1.60 60 foots. I was not aware of any "Pro" gears for the 8.8" at that time, not sure if that has changed. But if you are running a ring and pinion with a ratio of 4.88 or taller, especially with an automatic, I doubt you should have any gear issues. With the 5.13s, the pinion had 1 less tooth than the 4.88s, and I guess thats where the problem was.