Ok gents I must confess that I did not do as you recommended. I came up with a alternate solution try to stretch the sill using weight. Not having weights to attempt my idea I used the trucks weight to see if the sill would stretch. So I jacked up the truck by the differential and placed the bent sill under the tire (see photos.) It did stretch but would curl up again when the weight was removed (as expected). So I decided to cut the sill at approximately the area where I considered the bending originally occurred. Once I did that, I placed the sill under the trucks tire and this time the sill stretched to its flat form.
See attached photos.
FOR YOUR INFORMATION : I will be welding the cut areas once I finish dry fitting the bed.
