I have a strange problem with my jinxed 66 389. It has been overhauled bored .030, mild cam HO manifolds rebuilt tri-power, Pertronix Ign. 4 or 5 times if I got on it enough to open the carbs but not hard enough to brake traction the engine would then run rough and shake and act like it was flooded (loading Up) It would almost die. I could shut it off and wait maybe a half hour and restart it and it would idle smooth. It did this after the Pertronix was added and before and after the carb restoration. Is it ignition? all but the last time it did it getting on it. The last just cruising about 50 after driving about 30miles. Incidentally , I had Mikes Tri-Power rework the carbs -this man knows his carburetors.