[obijuan]

caster is adjustable with pinion shims and you are somewhat under spec but in reality 6 degrees is pretty good. I do not think you need to adjust the steering box. I think you could benefit from a strong dual stabilizer or a really good single. Fox racing steering stabilizers are excellent at controlling much larger tires than you have. If you are just looking to firm up the feel then add that and you will be turning that as well as it controlling your truck from the road conditions. fox offers a universal stabilizer that you would probably like the feel that it would give your truck steering.

if you want to do dual, bds offers a bracket set 55374 and fox shock 98224011 x2. Thats way overkill but it will work reeeeeeally well.