It's not about the bulbs
I am assuming that you still have the OEM 2 bulb headlight system. If so, that is a very poor lighting system from the factory. The reflectors are poorly designed and very little of the side of the road is illuminated on low beam. The 9004 bulb low beam is only 45 watts - de-rated for longevity as compared to a standard 55 watt low beam bulb. Then, to top it off, there are long runs of undersized wiring through the headlight switch and low / high beam selector switch and eventually to ground. There are no relays to improve voltage to the bulbs. And, of course, as the lens degrades over time, matters only get worse.
The result of this OEM wiring is that there is less than 11 volts available measured at the bulb with low beams activated and engine running - and this is when the truck is new!. Voltage should be a minimum of 12.8 volts (American bulbs) and 13.2 volts (European bulbs) measured at the bulb to get 100% of the rated bulb's output capacity (typically rated in lumens). At 11 volts, illumination output is reduced to around 50% of bulb's rated output capacity. You can buy the best bulb in the world and it is not going to help with an OEM 2 bulb headlight system.
A 4 bulb OEM headlight system (called Sport Headlights) is a much superior system. It is relayed and uses two 55 watt filaments (outside lights 9007 bulb) for low beam and four 65 watt filaments (outside 9007, inside 9004) for high beam. The reflectors are of good quality and light up the roadway and the sides of the roadway very well on low beam or high beam.
- John