Check the orientation of your steering linkage; the bar that your tie rods thread into, and your pitman arm and idler arm connect to that same bar. Each end should be angled DOWN and to the REAR of the truck.
I did the same repair a couple years ago and missed that; which, ya know... my bad. Should've paid more attention when I disassembled. But I had it aligned 5 times at 3 different shops; none of them noticed, and it was within spec. But it was wandering all over the damn road.
Tried to install a steering stabilizer kit one night that was supposed to be a bolt-on, and was getting all kinds of interference when I turned the wheel, and then it hit me... "I've got this F-ing thing backward!"
Unbolted, flipped it, took it back for one more alignment the next day, and it's been good since.