Even after fiddling with steering since the mid 1960s, there are still things I see that make me feel like a dummy. I think the best thing at this point would be for us to figure out what sort of steering box you have. Once we determine that plus what the prior owner may have done with it, I'll bet somebody here will have an "aha moment" and we can offer some suggestions that are more valid. It sounds to me like the prior owner installed a kit from somewhere, but we don't really know. Could you post some digital images to Photobucket and give us a link? Never say never and all of that, but I've not heard anyone advise to adjust a box off dead center to make it drive straight. I could be misunderstanding your friend's thoughts, but that seems fundamentally flawed to me...at least I can tell you in all these years I've not seen a single steering box designed to work that way.
Just for grins, here is word for word what the manual for the truck says:
"The sector teeth are also cut so that when the sector is adjusted to take out all backlash at the center of travel or straight ahead position, there will be slight backlash at each end of travel, thus snugness of the sector in the rack teeth in a straight ahead position can be obtained without sacrifice of perfect freedom at extreme positions, right or left, of the front wheels." Meaning at dead center you'll have the tightest mating of the sector gear and rack teeth (teeth on the ball nut) and as you turn to the right or left that clearance will diminish.
