1952-59 Ford napa resistor for duraspark II

Does anyone know what resistor can be used on the + coil in the run position? I have 12 volts going to the coil in the run & start position. I read a post a while ago with a napa part number but I'll be damed if I can find it now.I recently had my coil split so I want to try a resistor.
Thanks,
Kurt

 

your old coil probably had an internal resistor it may have been marked as such.do not put a resistor on new coil unless you know it requires one