I have a 54 bed installed along with my 54 cab on a 53 frame. Yes, the hump over the rear axle has been modified (lowered and boxed). Everything fits as you can see on my truck pictures. I would like to try installing the cross sills in the original locations if possible. Would anyone with an original 54 bed be willing to give me the measurements, front to rear, of placement? How many inches to the center of the first cross sill, from the front to the center of the second, etc. I don't have any trucks around me to look at. Dan