The 1998-2000 Rangers are not equipped with a VSS (Vehicle Speed Sensor). The PCM (Powertrain Control Module) receives vehicle speed information from the antilock brake system rear wheel speed sensor. The raw signal from the ABS/VSS sensor on the rear axle goes directly to the 4WABS module where the signal is corrected for tire diameter. Then the corrected signal is sent to the PCM, speed control, cluster, etc. In this system, the PCM and speedometer is an end user of the corrected VSS signal.
So you will need to reprogram ABS module if you will be changing the Pulse per mile count, this includes changes tire size, axle ratio, or tone ring location.
Dakota Digital makes an adjustable pulse interface: Universal Speedometer Signal Interface
$85, but it allows you to change things without having to reprogram ABS each time
Not sure how the ABS module will react to the VSS sensor and rear wheel sensors have such big change(axle tone ring to driveshaft tone ring), it shouldn't matter BUT, those are always "famous last words", lol.