[Mike C]

There were some half ton Dana 60's. Mostly 67-68 big block trucks. They were a 6 lug semi-float design. But it would not have been original in a '73 and up. That would have been a 12 bolt until earlier 80's.

My own opinion about changing gear sets into different housings, is if you have to ask, you probably shouldn't. It's not rocket science, but it does require several tools most DIY'ers don't have as well as a little experience.

If you are willing to read, learn, and spend some then go for it. But Google is much more useful than asking this to a message board IMO.