Thought I'd share that I finally discovered a nagging flat spot in acceleration, especially from idle that I've been having for some time. I had kept thinking it was just in need of better carb tuning, or maybe a bigger accelerator pump or getting the right combination of jets. It's an 800 cfm Edelbrock on a 408 stroker. Turns out the counter weight for the flaps was coming down and getting caught in the spring. A 2 dollar picture hanger bracket, a machine screw, and a couple nuts and the spring is sitting well out of the way. She drives like a whole new car. For once it was something simple.