Tom,
Something to consider, for Square Body trucks, is to add relays for the headlights. Sometimes there is just not enough juice getting to the headlights. GM added relays to the trucks later in the 80's. H4 LED conversions may require relays.
There are many tutorials and even pre made harnesses.
LMC Has a harness:
https://www.lmctruck.com/electrical/...PLnWzEi17P-rQY
Greg