The primary resistance, with either a ceramic resistor or a nichrome wire from the ignition switch to the coil, and the bypass system was on every GM 12 volt ignition system up to the HEI ignition's introduction in the mid-1970's. If it was not needed, General Motors spent a lot of unnecessary time and money developing it, and installing it on millions of cars.
That being said, I'm sure a bunch of internet forum members who were probably filling their diapers when these systems were developed probably know a lot more about it- - - - - -NOT!
Jerry
