Thank you all for your further advice. I like the advice given by Hotrod Lincoln about building up the cast nub. I found this option:

https://66impalass427.tripod.com/id34.html

That example mentions welding a tab onto the reverse lever of a 4-speed version. Maybe I can do something similar for my 3-speed version. I will measure and find what I will need to activate the rod.

I cannot tell from the photo of the disassembled parts provided by DoubleDingo what his shift housing looks like. The photos in my previous post do show the one in my friend's working transmission to be different from the straight drive version. That straight drive version looks like the one in my not working transmission, both shown in my 2nd photo.

1950 GMC 100 Panel Truck, 1958 270,
3-spd Saginaw with BW OD,
3.73 12 Bolt Differential from a 1966 C10,
Front Disc Brakes
Bought it in pieces 9-1976, driving since 6-1978
Follow in the DITY