Is there a diff between the frames of a 79 f150 2wd and a 4wd?

I have found a real clean 79 150 2wd and am thiking about making it into a 4wd can it be done or are the frames diff?

 

The frames are different. It could be done, but it's not a bolt on deal.

 

what all is diff? I have a severely rusted bronco could I steal all the needed parts off it and use? if its just the cross braces then I think i could swing it.

 

The frame is different from the firewall forward.
You can convert a 2WD to 4WD but, as Mark a. said, it's definitely NOT a bolt in deal. There will be a lot of welding involved.
Crossmembers are different, motor mount towers mount differently, steering is different, etc.
It's been done many, many times but there is a lot of work involved.