Have always been told full 12v will generally cook a factory ignition module, and have yet to see evidence otherwise. Thus my practice is to leave ballast resistors (resistance wire in my Lincolns) in place UNLESS module is changed too. Have one car burning complete Pertronix system -- coil and replacement module -- at full voltage. All the others remain 10v as they left the factory. Does cut down on final ignition voltage, but I figured closer to 35,000 volts from a coil otherwise rated 45,000. Bill Robertson #5939 >--- In dmcnews@xxxxxxxxxxxxxxx, "John Hervey" <john@xxxx> wrote: > Bill, The way the Pertronix is made, you could run it with straight voltage > and get more punch. My not last but 1 or 2 years instead of 4 or 5. > John Hervey > www.specialtauto.com [long quote trimmed by moderator]