If you can get to a counterperson who cares you may get lucky. AutoZone started by buying NOS parts from dealers & parts stores going out of business. There is still some stuff buried there. O'Reilly bought CSK (who bought dozens of smaller parts brands) and if you can get someone to get in touch with the Home base in Missouri they can do a lot. When I worked for CarQuest the computer searched the stock of every CarQuest store & warehouse in the country. A good counterperson at Napa can do the same thing. None of these places teaches their people to do this anymore. You might find some old guy that has been doing it a long time or some young person who likes to play with his computer. You machinist might have better luck because he will get to the commercial parts guy.
The folks on the Stovebolt website specialize in old GM trucks. Someone there might be able to help. LINK TO STOVEBOLT
"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
