Very brief history:
Prior to 1940 and after the period of using kerosene or acetylene fueled lamps, cars were equipped with headlights that were constructed of a headlight bucket with a replaceable filament bulb. The headlight bucket served as a housing for the components of the headlamp including a mount for the bulb, a larger reflective surface used to broaden the beam of light emitted from the bulb and a clear lens to protect the bulb and reflector and to a degree aim and focus the light emitted from the bulb. Typical problems with this approach were that the lens and reflector were not always tightly sealed and contaminants could enter the headlight bucket, coating the inside of the lens and the surface of the reflector. Proper maintenance of the headlight bucket could reduce these problems, but there was a diligent effort required to remove the lens for cleaning both lens and reflector. Further, the reflector could get damaged from frequent cleaning, reducing its' efficiency.
Beginning in 1940, Federal law required two 7-inch sealed beam headlamps on each car. The sealed beam lamp was an integral, sealed unit of filament bulb, reflector and lens. The stated purpose of the sealed beam lamp was to provide a new, clean reflector within a sealed chamber that would not get dirty, easing the motorists mind with reduced maintenance. The sealed beam lamp was equipped with two filaments that today we call low beam and high beam. In 1957 Federal law allowed four headlamps of 5 1/4-inch diameter; two headlamps served for low beam and the second pair provided additional light to serve as high beam.
More history is available that can excite your interest.
Headlamps are still available today in both 6 and 12-volt, 5 1/4 and 7-inch sealed beam. The dim glow of traditional sealed beam bulbs is due to at least two factors. (1) low light because of damaged wiring, corroded terminal connections or low generator output or (2) lower actual light levels compared to the newer cars to which we have become accustomed. For a time, auto accidents were considerably more prevalent at night than during the day for reasons including poor night visibility. Modern lamp technology achieves considerably better results for night time driving, possibly reducing poor visibility as a cause for increased auto accidents Some in our hobby are updating their headlamps to more current technology. Replacement options can include Halogen, HID and LED.
Which one should we select, are these options viable and do they interrupt the preservation of the old style?
Some of these bulbs draw considerably more power and care must be taken not to overheat existing wires and switches. In these cases, a relay is required to directly connect the headlamps to the battery, using a lower power relay to "throw the switch".
I found no searchable threads on this forum for "headlight" that addressed any conversion discussions. The following website (http://www.danielsternlighting.com/home.html) has very good information on conversion to Halogen but is a sales website which is not endorsed by this forum or by me personally. Other discussions on this topic were found on the HAMB http://www.jalopyjournal.com/forum/threads/halogen-vs-sealed-beam-headlights.312933/ and the Ford Barn: https://www.fordbarn.com/forum/showthread.php?t=47571. Wikipedia also has interesting but non peer-reviewed content: https://en.wikipedia.org/wiki/Headlamp.
I was hoping to provide a concise guide to a conversion; that is not possible. There is much to consider in a conversion and your participation with your experience and knowledge are more than welcome. Frankly, I am going to stay with original lighting, I have other more pressing priorities. When the time comes I would consider Halogen with a relay switch.