I'm still running 6v electrics in my 49 3100. To get it running 5 yrs ago the new Napa 6v battery set me back $120 and is still doing it's thing. Shortly after getting it roadable the regulator would take a tap or two to start charging. A simple cleanup of the contacts and adjustment of the relay points corrected that. Once after a good engine washdown the generator stopped charging, a simple swap out of the brushes corrected that. I drive it every weekend and it's not failed to start and run for the past 5 yrs & 21K miles. I wanted a tach and power port and decided to add a circuit just like moparguy linked to and the truck now has a separate circuit that can provide up to 10 amps at 12v. The tach is great to have and the power port has recharged my cellphone & works a Garmin GPS when the need arrises. If it had a modern radio it would power it also. For a Christmas parade I plugged in an inverter and powered a string of blinking lights I had draped around the contours of the truck.
All that said if/when the battery or 216 bites the dust I'll be going to a complete 12v upgrade. And integrate a big ole third brake light where all those tailgaters can see I'm stopping.......
