have you checked the voltage at the ballast? (coil side) You'd be amazed what anything below 9v at the coil will do. After that I'd go back to the basics. Go to TDc, unhook the vac advance, turn the carb mixture screws all the way in and back out 1.25 turns, start it take the idle up to 2200 and set the timing at 36*. Back it down to 800rpm adjust for best vacuum reading. take it for a spin. If it's still acting up, drop that carb in the can and get a decent one.