360 engine vibration

Yep I wasn't sure it was the damper either But it has got rid of a bad pulley wobble. So still progress. I've converted ignition to hei. Removed mopar module and ballast resistor. Made no difference Pulling plug leads whilst running drops all cylinders. When running it's a steady 20 on vac gauge. It' reminds me when you have twin carbs and one is being lazy giving less fuel.