Alright. Engine timing is all good. I didn't realize the cam gear had a cover. I found all the marks.
I did more looking around today and found that the distributor "star wheel" was damaged while looking at the cap and rotor. One of the teeth was bent upwards and not passing by the impulse pickup. I don't know how that could have happened.
Anyway, I tried to remove the shaft to replace the star wheel, but the cross pin on the shaft wouldn't budge. I couldn't see any way to secure the dis without putting it in a vice and damaging it, so I bent the wheel roughly back into shape, which went better than expected. I was able to get it more or less in position.
With everything re-installed I was surprised to find the car ran more or less the same. This is the first time I've dealt with mechanical ignition timing, so things have been slow to take, but I think I'm getting the hang of it. At idle, the ign advance is about 10*, which I believe is about right. When you blip the throttle, the timing jumps immediately to 30+*. Is that how its supposed to be? I tried disconnecting the vac one to test the centrifical aspect of the timing advance and it works. The car still drives about the same, maybe a little better, but it feels like its breaking up/misfiring until around 3-4k (depending on throttle) when it clears up. Short of trying to find a good used dis, anything else I can check?
Also, the vida diagram showed a valve between the dis vac line and the manifold. The part number was for a one way valve. This can't be right, since the valve doesn't let vac out of the dis pod and the timing can't return back to rest. (verified this with timing light) So I took that out, but it still breaks up. My coworker thought there was supposed to be a delay valve there. That makes sense to me as a culprit for why the timing advances so quickly with a throttle blip. Am I on the right track?