I couldn't find a source for them, so I wound up making a few. I gave my extras away, so I don't have any left. But, here's a thread that tells you
how I made the odometer reset knobs.
BTW, the picture posted by the OP is my dash with one of the reset knobs I made.
One more thing, there are two different lengths on the shafts depending on which speedo you have. I believe the ones I made are the longer ones, as you can see how far it sticks down under the dash. So, you can use a long one where a short one will go, but not the other way around.
Edit: Be sure to check up inside the speedo where the reset knob attaches to. Most often, the rest knob is missing because the rod in the speedo has broken, allowing the reset knob to drop out. :eeek: