[OrrieG]

I would absolutely make sure the frame and your suspension is correct and not tweaked. If it is it will show up when you start driving it. Shimming the bed will make it look right but I suspect the bent frame will induce a little rear bump steer. I see trucks all the time with bent frames driving down the road looking like an old coon hound with the driver doing a perpetural left turn to keep them going straight.