yeah, what Tiny sez for the tail lights, and consider adding a 3rd brake light higher up, the main problem with the tail lights on the older trucks is they're just physically too small and low - no need for relays on the tail, they don't draw all that much current, but make sure the wiring is all 6V sizes, heavier than for 12V, long wire runs make for extra resistance that cuts the amps delivered - you might also want to get a battery tender if the truck regularly sits unused for long periods
Deve, if you have problems starting a truck that's kept in a living space climate, it's got nothing to do with 6V, and I'd be surprised if a 12V battery would crank well sitting outside in below zero weather, winter in a cold climate takes mitigation even on new vehicles, like a block heater and battery blanket .... if the problem is simply the carb drying out [they're vented, so fuel evaporates over time], learn what it takes to start it under those conditions, GM put manual chokes on these trucks for a reason - failing that, just keep a 12V battery booster in your hot garage and hook'er up after the truck's been sitting for a long time, temporary 12V won't hurt anything but will make that 6V starter dizzy
Bill
