[SKRWZ]

Here is an online speedo gear calculator to help with 1998 and older vehicles that have had a tire and or a gear change that may need the spedometer corrected

NOTE: 1999 and up F 150's can use a progammer to corrrect this or a dealer may be able to Flash the PCM

I used this myself and it works well.

http://www.lowpricegears.com/GearCalculator.html