no fire

73 318 car was hard to start when hot now will not fire at all. replaced the ballast resister and the pickup in the dizzy. had the ecu tested at advance and the coil checked they said it was all good. i have power to the positive side of the coil when the switch is on but no fire out of the big wire in the center to the dist cap. what am i missing? all parts good but not firing???:spiderma: