Working on 1954 ford 239 ohv. The problem is car will start and run seams to be missing. Took it for a ride ran so so and was missing than let out a back fire and died no spark. The car was towed and started ran for 20 min. at home and next day went for a ride went about 2 blocks and died again no spark again the coil and points and condenser were changed not long ago. any info would be great help thanks and the car is still 6v with a 12v in trunk with a separate push button under dash and 12v solenoid just to help spin over during starting?