The Stovebolt Site Forums The Parking Lot Big Bolts Lopp sided truck.

Do you have any other pics of the truck from different angles?

What does it look like from the rear? Does the cab line up with the bed?

If the cab were sagging, you'd see it against the bed. It can't be a spring problem, if it was, everything would be sagging in the same direction, including the bumper.

Do you know if that truck has ever been hit before? it is possible one of your frame rails may be up or down on one side on the end where the bumper attaches.

Try this, park the truck on a flat level surface, preferably a garage floor put it up on 4 jack stands directly on the frame so it's off of the suspension.

make sure all 4 stands are equal height & the frame is level. Once it's off the ground and level, measure the height of the frame rails to the floor.

This isnt the best way, but it will tell you if something is off on the frame. unless you can get it on a frame machine.
The frame machine will give you an exact measurement.