[DetroitDan]

I have pulled apart several trucks that did not have body lifts, and the body mounts were rotted through, particulary the frame tabs where the mounts sit. Has nothing to do with the blocks holding water, the mounts themselves can hold water. If the blocks are installed properly water can't get inside them. Also, a body lift can make it much easier to clean the underside of the truck, you can get at places with the hose or pressure washer that otherwise you couldn't. Especially helpful in a truck that gets muddy.