Hi Bill,
The Westin 92200 is not what you need. It is a mounting kit for mounting a Westin rear bumper at stock height. You need a PER6522. It is a polyurethane rear bumper gap guard that take up the space created between the rear bumper and bottom of the tailgate by having the bodylift on the chevy truck. The PER6522 is $30.99
Thank You,
Jon Snyder
4Wheelparts