Hy Bats62Chevy, you can go larger in wire size with no problem, even though it probably isn't necessary, it's when you go smaller in size that you could create problems. A ballast resistor is a device that lowers the voltage in the primary ignition circuit of a 12 volt system, [from 12 volts down to 6 - 9 volts] it is usually mounted on the firewall, a wire from the ignition switch is connected to the input terminal, another wire is connected to the output terminal, that wire goes to the positive coil terminal on a negative ground vehicle. On vehicles with an "R" terminal on the starter solenoid, a wire runs from this terminal to either the output terminal of the ballast resistor, or direct to the coil positive terminal on a negative ground vehicle, hope that helps.
