I didn't really pay attention to the two ballast resistor part. Did you buy the car with the Mallory already installed? I could imagine somebody adding a resistor if they thought the module was overheating from too much current. But it's obviously not what the instructions call for. If it was mine I'd probably start from scratch and wire it up exactly like the instructions say, and make sure that all of the connections, including the distributor ground, were clean and solid. And also measure maximum charging voltage at RPM above idle speed. The external regulators can allow 15 volts when they're working correctly and I assume more if they get out of adjustment. Maybe somebody tried a bunch of stuff to fix/bandaid an overvoltage problem then never removed their attempts after they fixed the real problem.