HEI ignition troubles

I don't know. I dislike "throwing parts" at a problem but it might be time. You don't have a spare dist you can substitute? You don't even need to install it, just connect it and finger spin the shaft

Coils do not need to be grounded. The connections are all done by the two primary terminals and the high voltage tower. Secondary (high voltage) is internally connected to the primary, so it grounds through that