OldIHC

Has anyone converted lights from a 6 volt to a 12 volt and what or who is the best method. I was also looking at my brackets below my headlights and it looks lik they might have had parking lights or blinkers below them? Is that possible on D-series trucks?

All you can do is change 6 volt bulbs for 12 volt ones. Most sizes are available. Other options like putting them in series aren't smart. The little lites would be parking lights. Most old vehicles had them. Signal lights weren't mandatory til 54 and while some cars had them, or they were available as an option, prewar trucks didn't.