When you change the rear end gears in your Mustang you will need to recalibrate your speedometer either by installing a new speedometer gear if you have a 83-95 Mustang, a speedometer re-calibrator (SpeedCal) if you have 96-04 Mustang or a Ford Racing speed changer if you drive an 05-up Mustang. Our Mustang speedometer gears are inexpensive and only take a few minutes to replace! Check out our speedometer gear installation instructions for a full write up with pictures on how to change the speedometer gear in your Mustang.
