Hello all. Ford has made such a HUGE deal about their F150s frame and how it is fully boxed and such. Why do they still use C-channel frames on the F250, F350, and F450 trucks? GM has been using fully boxed frames on the 1500, 2500HD, and 3500HD. I would think that the fully boxed frame of a GM truck would make the vehicle a stronger truck. You hear the Ford guys talk about frame rigidity when they blab about the F150 and then sing a different tune in that the F250 and F350 needs to have some flex so they use a C-channel. What gives?