George (OP),
I wanted my freshly restored fog lights to remain stock, but take advantage of modern LED technology. I looked for a warm color temperature LED bulb that fit the original socket but could not locate anything so I made my own.
It wasn't that hard and I'm really happy with the results.
I unfortunately took no assembly pics but I'll do my best to describe the project.
Found these LED bulbs on Amazon 2 yrs ago - 6 watts, 550 lumens, 3000 K color temp. and 12 volts. All I had to do was mount them on my old stock bulb bases.
https://www.1000bulbs.com/product/113698/PLT-300221.htmlClick to view attachmentClick to view attachment I took the stock bulbs and used a heat gun to separate the glass bulb from its base. Once you get the base hot you can carefully twist the glass element back and forth(with gloves) to loosen it from its base. Then disconnect its leads by melting the solder on the bottom contact points of the base to completely remove the bulb leaving an empty base.
It would be easier If you could source the correct blank base as a starting point - but these are an old, unusual base type and I could not find them.
I cleaned out the remaining adhesive from the base (a powdery residue) and soldered thin insulated wires to the new LED leads to extend them about 1/2" longer than the length of the empty base. You want the stripped ends of your new leads to pass through the electrical contact points on the bottom of the old base so you may need to drill a small hole through any remaining solder. IIRC polarity did not matter with these LED units.
Leave yourself about 1/4" of space between the top of the metal base and the bottom plate of the LED assembly once the new leads are soldered to the bottom of the base. That will leave you just enough room to inject clear epoxy into the base before seating the LED assembly on top of it.
When the epoxy dries you have a solid, complete LED bulb assembly that fits perfectly in the stock foglight sockets! These bulbs are equivalent in brightness to a 50 watt halogen lamp and have a warm vintage glow like stock bulbs.
With respect to mounting a brighter LED bulb in an "incandescent" housing, keep in mind that the stock foglight retains an upper beam cutoff guard and these bulbs project a 360 + degree pattern which hits the stock reflector in similar fashion to a stock bulb. Theoretically they should not blind oncoming drivers and provide a very similar beam pattern as the stock bulbs.
I am very happy with the results. My objectives were achieved: stock appearance and fit, brighter more effective light output, warm vintage color temperature (not white or bluish light), less drain on the electrical system and longer life.
Hope this inspires others to try it.
-Scott