"While the bodies will shift to aluminum, F-Series models will continue to use separate steel ladder-type frames, which are the foundation of the trucks’ towing and payload capabilities. The frame of the F-150 is a new design that is stronger, yet 80 pounds lighter, than the 2014 version. " Maybe that means C-frame? http://www.nytimes.com/2014/01/12/automobiles/autoshow/the-f-150s-aluminum-diet.html?ref=automobiles
"Ford engineers said the F-150’s body and box strength also comes from the combination of structural adhesive — basically industrial glue — and some 4,000 rivets used to join much of the aluminum, replacing about 7,000 spot welds of a steel truck. " http://www.nytimes.com/2014/01/12/automobiles/autoshow/the-f-150s-aluminum-diet.html?ref=automobiles
Hope they still remeber the experience learned from JLR's aluminum body when JLR was a part of PAG.