So I got to looking at the remaining third loop slide and figured out that both upper third slides should be the same. I went to my parts bin and rounded up a crook of close to the same bore (it is either King or conn giant Eb) and some King tubing that is not an exact fit, but pretty close and worked on making them fit together until I had something "dry fit" that looked like this:
and was the right size:
Then I worked on making everything nice and even, worked on getting it to reasonably fit the slide tubes, hold air and slide, and polished it up so it looked like this
Thanks to the super plain style of the Olds ferrule, the only real visual giveaway is the ferrule thickness. The slide is significantly lighter than the factory one.
I like that every crook on the valve cluster is a functional slide, that the brass is nice and thick, the valves are impressively great and the bracing is solid. There are a few odd things about the horn, though, like the top of the pistons:
