Bobby W,
I just bought a new "rust free" cab for my 55/1st 4400 truck. It had the same dent you describe, although I didn't realize it came from a over extended door. My friend who has a bodyshop used a stud welder to pull it out. My concern was a distored doorjamb, so I made a
pulling jig that attached to the both hinge pockets for the "big pull".
I measured both door openings on the old cab and compared them with the new cab..I concluded that to do it correctly, you need to hang the doors and then pull the jambs if needed. I haven't done this yet!
Stuart.