dgc333
Well-Known Member
In typical mopar fashion from back in the day a ballast resistor ignition is theoretically superior to one without (kind of like left hand threads on the left side). A ballast resistor by definition is a resistor that changes its resistance with temperature. Using one to limit the current to the coil protects the coil from over heating at low rpm because it heats up an increases the resistance. At high rpm where current isn't flowing for as long a time between sparks it cools down and the resistance is reduced allowing more current to flow allowing the coil to potentially have a hotter spark. The other feature is it can be bypassed during cranking to give a hotter spark to help the engine start better.
Ford and GM either useed a coil with an internal resistance or an external resistor wire that allowed that allowed the coil to run at full battery voltage all the time. The down side is you didn't get an increase in potential output at high rpms or the boost for cranking.
As for the misfire with the ballast and not without; are you providing power to the Unilite down stream from the ballast? The Unilite should be powered with battery voltage and only the coil should be feed via the ballast. You may have been right on the edge of misfire with the old engine and the added requirements on the ignition with the stroker it was pushed over the edge.
