Just a follow up to my carb issues. I took the Dart to a local engine building shop and the tech took an interest. The nuts and bolts (with my limited skills to explain). He worked on my distributor for over an hour to give the big cam more advance at lower rpm. He suspected the car had low vacuum pressure at idle with the big cam causing the issue, and not dirt in the carb. He set the valves and made minor adjustments to the carb but never took it apart. I had the car for a 2 hour ride (at low rpm 45mph). No fuel dumping, idled great and will rip the tires off on take off. Car never worked better. Thanks for your insight that the car should work all day if set up properly. Cheers Ron D