[lackingmind]

You need to change the drive or driven gear on your speedometer cable or in your transmission. These changes in the speedometer calibration usually occur because of rear-end changes like when I switched to 3.73 gears in the rear. If you know your gear rations in your car or if the transmission was changed you can find out what drive or driven gears you need. If not you can drive your car along side another car both doing 60 miles an hour. Take your speed and divide it by their speed to get the ratio of the adapter you need. I believe that was correct I may not be right. Go to Autometers website and putz around the mechanical speedometer area and you will find reference to this along with exact instructions, as well as link to a mans shop up North that will make you a ratio correcter that can be screwed in between the speedometer cable and teh transmission housing without having to change the drive and driven gears. Hope this helps. Shnook the Cook thats Lackingmind.