I don't know of any specific sites that explain how its done or whats involved, but I'm sure you would have to change, move or weld some new body, bed mounts etc. Probably will have to remanufacturer the radiator mounts etc.
I know the track width on the 80s trucks is wider than the 50s trucks. Since your doing a 4X4 it may not look that bad, however on a two wheel drive, I think the track just looks too wide. That's just my opinion. No harm if others don't agree.
Good luck with your project.