Richard,
Here is what may be some helpful info from one of the available online Parts reference resources for
your '46 clutch linkage parts.
Screenshot below is extracted for easier viewing. The
red arrow indicates the correct adjusting bolt (including dimensions) as GM# 598342. The
green arrow indicates the normal tension return spring. The
blue arrow indicates the "extra" tension stength return spring that was available if the regular spring wasn't up to the task. I made mention of the different return springs in case the one you currently have is also the non-truck item like your adjuster.
If you were to fabricate a replacement adjuster, you should probably be able to duplicate the "hook" end from the part you have and just get it to the specified length of the adjuster to meet your needs.
Good luck and hope you will return and show us what you were able to come up with.
Dan
