Auto. Transmission Speedometer Gears

Follow the link below to help calculate the proper tooth count for your application 

https://www.tciauto.com/speedometer-gear-calculator

Once you change the gears in your differential, you need a new speedometer gear to recalibrate your speedometer. They're inexpensive, and only take a few minutes to change. These Recalibration Gears fit 1983-1995 Mustangs.