My main leak is coming out the top of this thing, which I think I've ID'd as a vacuum amplifier. It's plumbed from the intake manifold on the bottom and runs between the vacuum advance and the charcoal canister. From what I remember it holds a vacuum on the bottom but doesn't seem to stop the flow of anything between. There's used ones on eBay, but I doubt they're in much better shape.

I'm tempted to try and pry the top off of it and see if I can glue it back into functioning, although part of me wonders if it's supposed to purge air out of the top.

The vacuum advance pod is pretty weird too. It's got two diaphragms stacked on top of one another. One advances the distributor and the other I'm guessing signals back to the system that the advance is on. Not sure if that part is working as that pod doesn't hold vacuum, but maybe it would if the advance was pressurized? I haven't figured out how to test that yet, maybe I'll apply vacuum to the advance and put a 2nd gauge on the signal one and see if it holds anything.