Good Day All

I'm in the process of getting the Dart ready for the Nationals. Part of the process was getting the trunk area re-shot so that it would look decent. When I drove it to the shop my speedo was not working. (worked fine last summer).
Anyway, the car is back from the shop and the trouble shooting began.
The culprit is that the speedo cable started to unravel at the end that if in the plastic gear. This basically hogged out the in inside of the gear to the point where the cable just slips. I have a new cable/casing put am in need of a pinion gear. The Dart is a Slant 6 with 3:23 gears and 14" tires. My service manual calls for a Dark Purple gear with 18 teeth. At this point I would be happy with ANY gear for a slant 6 (Output shaft with seven teeth.

Any one have a leads as to where I might find some?

Thanks to All who respond.

Omni