I'm here to help what little I can.
KC daylighters used to come with a pag46 150w sealed beam bulb (not the H3 bulb that is common on most off road lights)
I recently came across two pair of these lights. Only one pair had bulbs in them and one of those wouldn't burn.
So I set off on a quest to find bulbs.
KC part number is a 2627 150w halogen sealed beam. 200,000 candle power. (Discontinued, have been for years)
KC recommends a Wagner 4049 150w halogen as a replacement. Problem here is the fact that they are only rated at a 15 hour life span. Even KC says the bulbs do not last long.
I found a reference to a GE 100w aircraft landing light bulb. (PN#4537) These also have a short lifespan. Only 25 hours. I bought a couple of these bulbs, and they are very bright.....almost as bright as the KC original bulbs.
The aircraft bulb has an almost flat lens where as the KC bulb has a very convex lens.
I came across a listing for police spotlight bulbs, which were an 80w GE PN#H7680X 230,000 candle power bulb that is rated at 300 hours of life. This is an inferred bulb and puts out more light because it transfers less energy into heat. These were the bulbs I went with. I figured with the close candle power rating, and the fact they had a decent life expectancy, they were my best choice.
This is the filament in the original KC bulbs.
This is the filament in the new GE H7680X bulbs
And finally here is a picture of the lights on with the original KC on the left and the new H7680X on the right.
The new bulbs do not look as bright as the KCs, but they are dang close. I think the inferred output of the lights messed with the camera. That and I was next to a pond and there was a massive amount of moisture in the air.
The beam pattern on the GE bulbs are very pinpoint. But they give off a surprising amount of ambient light. A better "off road" light than the original KCs IMO.
I'll post back after running them a while to comment on the longevity of them.
Sent from my phone where correct grammar is difficult.