I'm gonna just take a shot here as I ran into the same prob. not too long ago with a friends rod...his turned out to be a multitude of things but the worst was his dist.- he didn't have a "curve" it was more like a corner. The weights were so light for the carb. that he had installed that as soon as he hit the gas it threw the weights inside wide open. We got a curve kit from ye ole parts store & it improved 1000*.............worth a check huh?