project - the truck under discussion here is a 59, already 12V
the difference in 6->12 is the 12V coil needs resistence added under running conditions, but under cranking conditions the starter is drawing so much that the coil, already getting reduced input because of the resistor, might not have good enuff spark to fire right up ... so they set up a way to give the coil full 12V when cranking only .... the 6V didn't have an ignition resistor
if you're converting a 6V, you can use a coil with internal resistance to avoid needing the external resistor or the bypassing
Bill
