crosleyfield,

1. An alternator is probably more reliable and more powerful.

2. 6v alternator is expensive; 12v alternators are relatively low-priced.

3. Alternators can provide more current and generate more current at lower revolutions.

4. Generators look original.

Usually a person converting to 12v (and who does not have a working 12v alternator) will change to an alternator. Search this forum on "alternator" to find out about mounting them and wiring them (and selecting a one, two, or three-wire alternator). Also, read about internal vs external voltage regulators for alternators.

Ask questions - there are a lot of people on this site with a lot of experience and a wide variety of opinions on how to deal with alternators on these old trucks.

Tim