Plastic gear is not large enough diameter to engage with output shaft gear. Not enough teeth OR not physically located in the correct spot to engage with o/shaft gear.
I would imagine the pinion would be installed on the bottom if mounted on the driver's side of tms. To operate the speedo from the passenger side, pinion would be mounted on top of o/shaft gear. Otherwise, plastic gear would have to have opposite angle of teeth to turn speedo IF installed on the bottom pass side. I don't think The General would make two different designs of plastic gears. It would be real confusing to parts people and the customer in ordering correct parts.
Kind of like ordering valve cover gaskets for a SBC, out of stock, but, we do have them for a '79 Malibu with 267 CID automatic, A/C, P/S.
Everett "OBJECTS IN THE MIRROR APPEAR QUICKLY UPON RAPID DECELERATION"
[This message has been edited by Everett#2390 (edited 02-05-2003).]