I haven't tried holding it at 4000 then flooring it. I tried 3000 because I figured every bit of advance should be in at that point.

I have no way to test WOT fuel pressure unless I install a remote guage. I'm running Champion RC9YC plugs. The Edelbrock instructions suggested RC12YCs and when i used those, it dieseled after shutdown. The 9s stopped that. When I tested the cranking compression in cylinder #6, I looked at the plug. It wasn't directly after a hard WOT run so the appearance may not help. It was the amber/tan color with no speckling or spots.