Bill,
I wondered about that. wasn't sure if by 58, they had threaded the shift lever. I have a 53 Chevrolet 3100. I replaced my 3 speed shift knob. It just a had splines running parallel with the shift lever. Mine was a NOS shift knob. I actually had to drill it out slightly, in order for it to slide onto the splined end of the lever. For the last 1/4 inch, I had to wrap the knob with a rag and tap on it with a small rubber hammer. Hope this information with help you.
Rugo
