I don't have Zeniths, but all four of the items on the right side of your picture are part of the bellcrank assembly. One nylon sleeve goes on the post sticking out from the engine with the flange toward the engine, the spring goes over that (with one end in the hole in the plate and the other on the side of the bellcrank, and other sleeve slides into the spring with the flange at the top. The bellcrank goes no next, and that black square clip fits into a groove on the post, holding the bellcrank in place.
Thanks Steve, and everyone! I think Carl told me the spring was available, or maybe he had one... Here's a progress image from this AM with manifolds removed. So my to do list includes:
1. Order coolant hoses and clamps
2. Decide whether to replace starter and/or battery cable
3. Replace sensor at rear of block coming from starter?
4. Replace sensor under front manifold?
5. Read up on cabin coolant bypass and determine whether it was done correctly by my first vintage BMW mechanic (now retired) when I first bought the car back in 2005, and decide whether to do this again?
6. Deal with slight seepage coming from base of dip stick tube
7. Vapor blast manifolds and refinish yellow cad linkage components
8. Check/replace vacuum and fuel lines
Going to be a busy Spring/Summer...
Also, there's always the slippery slope of "when do I stop" before this starts to reimagine itself as a "restoration"!