I recently swapped a 65 Galaxie 60 AMP alternator (old school with an external regulator) on the 57 Bird and it works great. I need to install a 5 OHM resistor across the the generator light bulb terminals to "excite" the regulator in case the bulb burns out. Were can I find a proper resistor and what kind? Radio Shack? Thanks.

57 Black Tbird 312/auto