Put the BG Mighty Demon back on car. Still has the same problem. So, I swapped the BG carb for a known to be good 750 Holley. Well, big improvement. The off idle flutter is now just a slight stumble when in park. The engine sounds much better but when I drive it I notice a jarring flutter as I accelerate normally and for a 383 I think my 4 cylinder VUE has much more power. Something isn't right with this engine and I can't figure it out. It feels like a dead cylinder or something. Because the Holley did make a noticeable improvement, I am getting rid of the BG carb (at a big loss) and getting a Holley (much easier to work with and adjust plus better performance for me anyway)! The BG carb is only a year old and I only put about 50 miles on it but I have waisted enough time with it. When the BG carb is on the engine the problem I am having is much worse.