I am in the process of upgrading my 1952 pickup's external lighting without converting to 12V and thought others here might find the information useful.
Pictures are posted at the following link (I can't seem to enable bbcode or else I'd inline the images):https://plus.google.com/photos/1016...71790989873000929?authkey=CNvcgPD10O2cfQ
First up, tail lights. Due to the license plate light, at least the lower right bulb must be white light. Due to the weird inclination of the bulbs, any solution must avoid being too directional. Lastly, the more lumens, the better. The best option I could find were these LED bulbs straight outta China:http://www.aliexpress.com/item/Pair...ke-Tail-Stop-Singal-Light/584926090.html
There are three COB emitters around the perimeter and a big COB in the center with a hemispherical plastic lens. They claim 100 lumen brightness per bulb and I believe it; you can actually see my brake lights during the daylight.
I recommend using plastic tail lenses rather than glass: the light transmission is much better and they don't break if you accidentally drop them on concrete.
The running lights in the grill have been previously converted to blinkers. With weak 6V incandescents and clear lenses, it was hard to see in the daylight. Even at night, it would be nice to have them blink amber rather than white. Due to the horizontal orientation of the bulb, it is imperative to have non-directional emitters. This is the best bulb I could find for the application:http://www.aliexpress.com/store/pro...Tail-Reverse-Lamp/808279_1050627590.html
These pineapple style LED bulbs work great for this application and are much brighter.
In order for the turn signals to work with LEDs, the flasher must be swapped out. This is the only thing I could find that fit the bill:http://www.ebay.com/itm/LED-NEW-6-v...suzuki-/251429558993?hash=item3a8a5e9ad1
The only thing I might do differently is to pull the light housings and paint the inside white or reflective. But that was a bunch more work and I think that the improvement would be marginal at best.
Oh, and dielectric grease is your friend.