I run 4 degree caster shims since the truck has been lowered some. How much does the front end raise if you steer it left to right while setting still? On a slick garage floor, mine doesn't raise all that much, a lot of caster will raise it. It should track straighter the more you add, get to much and its hard to steer at slow speeds. Does the wheel return to center after a turn at normal driving speeds? This is also a result of caster, if it whips back straight, to much, if you have to pull it back, not enough caster.
Give it another 1/16" toe-in and double check the tire pressure. You might also tweet the gear box sector adjustment just a tad tighter.
Joe
