After a four week hiatus due to an especially brutal winter, working on other vehicles, and other obligations, I was able to get back to work on the cab yesterday.
First up, a poll: What does the factory mark on the firewall shown below say? Chevy? A434? Something else?
I cleaned up the firewall, then welded up the holes for the three replaceable line clips, along with the hole for the clutch rod. The factory 3-speed will not be making a reappearance.