Hey Myron, Don't forget the clearance between the carb vent stacks and the bottom of the air cleaner lid. You are the one that solved this issue I was having a few years ago. If you remember, the car was nosing over at about 4500rpm. We all brainstormed on here for a couple days, the you suggested proper ventilation could be an issue. I went to a taller filter...… Wala, problem solved.