Frame differences

[70ford1]

Thinking of a new project but need some expert info before I invest any money into it. My question is this: Is the "frame only" from an F-100 the same frame as the one from a same year F-250 the same frame. I know the different components (springs-axles-transmission mounts-etc) are different but the basic frame, are they identical? I'm comparing a 1970 F-100 to a 1970 F-250--is the side rails (don't know the correct name) the same, or is one "beefier" than the other? Would the answer to this question be the same for all bumpsides from '67 to '72? I'm also talking the 133" wheel base.

[1971ford]

F250 frames are thicker. And it's 131" wheelbase

[70ford1]

Thanks 1971ford---Now I have to find an F-250 do some more comparing. May be back asking more questions---