I have been running factory Duraspark ignitions for decades, both factory installed, and as a conversion from points. On my FE powered Fairmont drag car, I ran a recurved junkyard Duraspark for over 30 years, with a MSD 6T ignition box, and on my 74 F350, I added another junkyard Duraspark with a factory blue Duraspark ignition module, and in over 25 years, never had an issue with either. Currently, I have a 428 CJ in my 59 2 door sedan, with yet another (recurved) junkyard Duraspark distributor, along with a factory Duraspark blue module. I have been driving the car for about 5000 miles over the past 3 years, and all seemed fine. However, last weekend, a racing buddy from 4000 miles away, came for a visit, so I let him run my 59 at our local dragstrip, while I ran my Fairmont. This was the first time racing the 59, with the fresh 428, and it seemed kinda weak, and he said that above 4500 RPM, it seemed kinda lazy. (on the dyno, pear HP was at 5400). It wasn`t misfiring, just didn`t pull as well as I thought it should. Anyhow, as an experiment, I bypassed the 59s factory firewall mounted external ballast resistor (no idea of the amount of resistance), and ran full 12 volts to the ignition. Next pass, the car picked up 4 tenths of a second, and he said it ran much stronger, so we left the resistor bypassed, and made several more 1/4 mile passes, and then drove it home, and I have been driving it some since seems fine. However, after doing some googling, I am seeing conflicting information. I have seen some opinions where they say to run 12 volts, other say it needs a resistance of 1.10 ohms, some say 0.7 ohms. Just wondering if anybody actually knows for certain. I have heard that there was "Duraspark 1", and "Duraspark 2" versions, supposedly the small cap models were the 1, and the large 2 piece cap were the 2. Since the only FEs with factory Durasparks, were used on 75 and 76 trucks, and all those that I have seen had the small cap, I ASSume the truck FEs were all Duraspark 1. So... to make a long story a bit shorter, I am wondering if running 12 volts will be detrimental to a long life of my ignition, or if I need to run a certain amount of resistance. The engine runs stronger at 12 volts, but don`t want to fry anything, as 2 hour drives to various car meets is not uncommon. I have heard that later (60s-70s Fords) used a pink resistance wire, at least on a points application, but no idea what factory Duraspark vehicles used.