I was doing my best to stay out of here because the LED fans will surely hate what I have to say...
IMO the only
really good LED headlights for these trucks (and the only
street-legal ones for sure) are the sealed beam 5"x7" LED replacements for the W/T grilles. TruckLite 27450C for example. These housings/reflectors are designed from the ground up to work properly with a diode instead of a filament and therefore have a proper cut-off and light pattern. All the drop-in 9005/9006 LEDs are just doing their best to imitate a halogen filament, which is pretty much impossible to do with a multi-sided LED board. No matter how you adjust the housings, you're going to have some light going places it wouldn't if you were using halogens. Anyone doing the swap can observe this for themselves, just look at the amount of light reflecting off of street signs and other elevated reflective surfaces after you put the LEDs in compared to the OEM halogens. Anyone who wants to dig deeper into this for themselves, check out this thread. It's a long and convoluted read with a lot of random discussion of other topics but there's a ton of good info on lighting in general.
https://www.gmt400.com/threads/spyder-headlamps-my-take-on-em-and-lighting-in-general.36647/
Long story short, the drop in 9005/9006 LEDs can be an improvement over the stock halogen composite setup for a lot of people, but mainly because they're able to run at full brightness with the wimpy stock wiring. A good set of halogen bulbs like Philips ExtremeVision and and upgraded wiring harness with relays like
@5vortec7 offers for sale will put the drop in LEDs to shame, and keep all the light on the road where it's supposed to be.
For those who think I'm just beating up on the LEDs without trying them, I actually have AuxBeam S1s in both of my '97s right now as I wanted to see the results for myself. They're not horrible, but they definitely put some light in places I'd prefer they didn't. At some point I'm probably going back to halogens.
All that said if you absolutely have to try some drop in LEDs, I'd go with the AuxBeam S1s or the comparable BeamTech option. Reasons being IMO the two-sided boards work better in these housings (despite what Ehall8702 said, I've seen one of these trucks using a four-sided model and they seemed to put light all over the place in comparison to the two-sided) and they have no cooling fan to fail, just a heatsink.