the stats, 8ba with 400 miles. pertronix in a bubba gm dizzy, new epoxy pertronix coil, new wires, new ngk plugs, new stromberg carb. while setting my timing the timing mark will jump around a bit. the engine sort of stumbles when this happens. the mark always jumps to the advance side. i really dont know what to look for anymore and its driving me insane. any thoughts? thanks.