I found out what the culprit was with my IBP distributor, when the vacuum advance kicks in it changes the points gap and the firing at higher revolutions becomes erratic. I tried to limit the arm on the vacuum advance. It was an 11 but I thought it still could be too much. It made it a lil better on the points gap. But I tried it out and still have the same issue. The breaker plate has virtually no movement, so there isn't any play. Anyone have any ideas? I wanted to keep it original but I'm to the point where I'm thinking of pulling it for a prestolite with Pertronix and be done with it lol.
jim