Tracking Issue

[dustykey]

My issue is that my truck seems to track all over the road. I really have to "drive" to keep it in the middle of the road. If I go over a ridge or rise in the road, the truck seems to track that way and not really come back to center on its own. I have a 72 SWB with a 2.5/4 drop. Up front I have 2.5 drop spindles with new standard height front springs from LMC. Installed tubular upper and lower control arms from CPP. New steering gear, tie rods, idler and pitman arm. In the rear I have new 4in drop springs, new trailing arm bushings and new shocks. New rear stabilizer bar (frame to diff. housing). I do not have any sway bars on this truck. Would that help solve my problem? I always thought sway bars were for body roll.