I don't have a timing number at 1250 where the vibration is most noticeable, but not too hard to get.
I used a piston stop to get on TDC before removing the old balancer and the timing mark was dead on. When I installed the new, refurbished original, balancer the timing mark on that one lined up also with the zero on the timing tab.

Timing is 13 at idle (around 750) with vacuum advance disconnected and plugged. I get 34 at about 2800 RPM. The timing is steady and consistent at idle and 2800. I did not pay a lot of attention to what it was doing as I was bringing the engine up to 2800, but don't recall seeing anything that might have indicated an issue.

VA is hooked up to ported vacuum. The carb is an original holley 4368 and the VA is hooked up to the port that the service manual shows as correct. I get about 47 degrees with the VA hooked up at 2800 RPM.

My intention has been to spend some more time trying to dial in the best timing and advance for this combo, but the vibration has put this on the back burner. The way it is setup, it runs pretty good. It starts easily, does not ping at least that I can hear, idles at a steady RPM, has good throttle response, and feels strong up to 5500 RPM or so. I had a wide band O2 sensor installed when I first put the engine back in the car and got the car on the road. I got the carb/ignition tune so it would idle at 14.2 -14.5 AFR and cruise at 14.7 - 15.1 AFR. Maybe a little on the lean side for ethanol fuel, but don't think it is pinging/detonating and don't feel any lean surge. I don't remember the WOT number, but it was ok as well.

I want to again thank everyone for the ideas and thoughts. I am trying my best to make sure the easy stuff to fix/adjust is done and nothing is overlooked before I resort to taking the drivetrain apart. I think I've got a replacement converter lined up that I should be able to get this week. So have a little more time to check and verify things before I dive into converter replacement.

Regards,
John