Reasons to keep a 6 volt system:
1, Stock, what it came with.
2, Parts are easy to look up.
3, If it works, why fix it?
4, Belts are the same as the parts book says they are.
Reasons to convert:
1, Lights are easy to find.
2, Accessory's are easy to find.
3, It might start better...maybe.
That is about it. Good news? You get to choose.
Ways to convert?
1, 12 volt generator.
2, 12 volt alternator, a: 1 wire. b, with external regulator.
The rest as they say is in the details. Want a modern ignition? Convert. Want a modern sound system? Convert. Want a stock radio? Keep what it came with. Of course there are ways around each of these but it gets more complicated if you add up converters to run a new radio or sound system on 6 volts. Or if you run load resistors to run a 6 volt heater motor and gas gauge on 12 volts. Your truck and..your choice. What do you want it to look like? Original? Custom? Or are you just trying to be dependable? Enjoy this is the fun part.