"Wats a ballast lol?"

If the car is old enough to originally have had a points ignition, then the hot wire from the switch to the coil would have been a resistor wire or would have run through a ballast resistor. Points would not take a full 12v all the time or they would burn up, so the OEM's put a resistor in the system that would cut the voltage to 6v after the motor was fired on 12v and warmed up.