first. measure to the frame not the fenders / wells. those could be off by cab mounts screw holes or other issues.
most likely its springs and or shocks. take shocks loose and do measurements. that will determine springs. shackles tend not to play a role unless they are broke. if springs check out shocks next. if those are good then well check your frame itself. or check frame first and work down.
Back to the actual suspension topic. Though the license diversion was good....
So you’re saying remove shocks and see if it sits more level-er? And if it doesn’t it’s the springs, if it does it’s the shocks.
I’d be “shocked” if the shocks are any good, even if they aren’t the main problem. They look pretty rough.
