How to modify a repro starter gear to work with a -39 throw out bearing
The starter gear on the left is a sifton gear that we modified to work with the -39 throwout bearing. We chucked it up in a 4 jaw chuck on the lathe and cut a 30 degree chamfer on it. The gear on the right is a later o.g. gear that was designed for the later waffle throwout bearing.
Here is what the incorrect set up looks like. Notice how the bottom of the teeth stick up above the throwout bearing. This set up will limit the span of your clutch arm.
Here is how the gear should sit in the throw out bearing. Notice how the bottom of the teeth are flush with the throwout bearing surface. If you set your trans up like this, you will have the proper amount of clutch arm travel.