kreymis:
NO! (No flame intended, Three50won.) The speedo/odo has to be corrected using a SpeedCal (Dallas Mustang) for the pre-1999 models. The tune is adjusted for shift points (automatic) and/or rev limiter but the speedo/odo cannot be corrected in the tune.
A SpeedCal costs about $100. You will need to do a little re-pinning of a connector but it is not difficult and the box fits into the interior of the console at about 1 o'clock. At least, that's where mine is sitting.
HTH,
Chris