[SCOTI]

Originally Posted by theastronaut

First thing- check the alignment. As much caster as possible (looks like you have stock front suspension so no worries about going too far), -.5 camber, and 1/16" toe in is a good starting point.

Check the bushings in the four link, track bar, and sway bar ends.

The "coilovers" are just coil springs over a regular shock, not actual coilovers. They're mounted wayyy inboard, probably for clearing wide tires? Mounting them that far in gives the body a lot more leverage on them, so it's harder for them to control body motion and may be part of the problem you're describing. Since it's a separate shock you could pull it out and try a shock with firmer valving if the alignment and bushings check out. Mounting the springs and shocks outboard of the frame would be ideal.

If I may add to the above....

The 4-bar looks to be 'in-board' as well. With the shocks & locating links all within the frame rails vs. out side it's going to require more effort than normal to keep it stable vs. the same exact truck w/the links & C/O's out-board of the frame rails.