Ignition coils and drivers need to be matched, some cases a bit of mix and match will work, but in many cases the results are problematic. Ignition systems are current based, so if the coil is too low of an impedance, it causes issues with the driver. Your coil being too hot is an indication that's it's impedance is too low and drawing significant current. Ballast or dropping resistors may appear to drop voltage, but they are is essence limiting current. Mallory makes good stuff, and if you're happy with the advance curve on that dizzy, I'd research the correct coil and/or ballast to run with it. When we encounter older engines with ballast resistors, we would wire a PB to apply full 12 volts to coil to allow for hotter spark at start up, just a thought. Mallory, MSD, Pertronix, and DUI are some of my faves. My Z runs a Petronix III with proper coil sans resistor. Timi will be A DUI recurved HEI. Hope this helps