You may have to get a different gear - some of the Top Loaders use a reverse twist. The actual speed sensor should be fine. All they do is make a signal for the number of revolutions of the output shaft and connect to the electronic speedometer with a pair of wires. Svthaulin, did you have to modify the hold-down clamp?
All Ford's transmissions that used a mechanical speedo used the same parts for the cable connection. This includes transmissions all the way back to at least the early 60's. The only hitch is as Paul stated, some used reversed speedo drives due to a passenger side speedo hole in the trans tailshaft.
