Ballast

I agree with 71 dart and the ballast "limits" current draw because the voltage drops when the starter pulls heavy current when starting. The ballast resister actually drops voltage across it and helps keep the voltage up when the ignition coli field collapses and produces the spark-producing a little hotter spark. The ohm value is .5 ohm on cranking and switches to approximately .5 ohms when the ignition switch is released and the engine runs and the alternator builds voltage to around 13 volts.