some more thoughts on this, kcwelshans
you say the PO put a "non adjustable" drag link on .... I don't think any drag link is adjustable, but I don't know about 4x4s
have you tried as 31,2,3 suggested to check steering box centering, then also taken off the steering wheel and reset it so when traveling straight the spokes are in the right orientation?
how far off of 'even' is your steering wheel movement? is your K truck a 4x4? has the front axle been replaced? is it still positioned properly and secure?
does anyone know if from the factory the steering box position is always exactly centered?
I'm not sure about the 60-66 trucks, but the 55-59 trucks have physical stops to prevent the wheels from contacting the frame or steering components, and those can be adjusted, maybe your truck is simply turning farther one direction cuz the stops are off?
I hate to see ya modify something that doesn't need modifying and that may lead to disaster one day on the freeway .... if it ain't broke, don't fix it, if it's broke fix what's broke!
Bill