rotorwrench
Well-known member
I wouldn't fixate on the voltage drop in the circuit too much. How many amps are drawn by the coil is more important than the voltage. The ballast is there to control the amperage in the circuit. The coil will work with a variance in voltage but needs a stable current flow for best function depending on the design of the inductor coil. The old Ford/Mallory designs needed a ballast on a 6-volt system. The round can type coils could take more heat so a ballast wasn't all that necessary until the voltage was increased to the modern 12-volt systems in 1956. The Model A coil was a can type and it didn't need a ballast.