There are many many many threads about this. I always recomend against it if at all possible. Especially with a '73 and up frame. It is a lot of work and you will end up with about a 3" body lift. And yes I have been there done that. I do admit that the '60-'62 frames are not the easiest to work with for what you are wanting to do. If you were to swap frames, I would suggest a '63-'72 frame, with '63-'66 being a nearly direct swap. But you will want to be sure to make the swap legally with the correct paperwork as required by your local DMV.
Here is a thread that I started on the subject:
http://www.67-72chevytrucks.com/vboa...d.php?t=481023