short box stepside box attachment.

[mikl911]

I am currently working on a 1969 short box step side truck. The box was not attached to the truck when I purchased it. I'm not sure if i'm missing pieces or I'm just missing something but for the life of me I don't see how the cab end of the bed attaches to the frame or any other part of the truck?!? Non of the cross pieces attach to the bed sides the only points of contact to the frame that I have are on the tailgate end. So what supports the bed with out the floor in place or even with it in place? Pictures please!