Classic/Antique Car Repair: Electric conversion-6 to 12 volt, external resistor, volt system

Question
I have a 1941 Plymouth pickup.
If I convert to a 12 volt system,
do I have to used a 6 volt reducer to connect to my distributor?

Answer
As far as the ignition system goes you need to install a 12 volt ignition coil. There are two types, one that requires an external resistor and one that does not. However that does not address the issue of the dash gages and the lights. If the truck is in very good condition I would hesitate to upgrade to a 12 volt system. But that is my opinion.
Brad