Advice on putting a 6.2 diesel in a 72' K10

[Truck Hippy]

I did several searches on diesels in 67-72 trucks but I didn't find what I was looking for. I know this has been done so I want to ask some questions. My goal is 30 mpg in a 72' swb 4x4. I sold my 72' swb 4x4 over a year ago and I'm having withdrawal. It wasn't anything special. It was rusty and beat up but it still got a thumbs up from a lot of people but the 350 was a gas hog. I'm half way looking for another one to drive and I want to put a 6.2 GM diesel in it. My questions are to the people who did it are,
1, Did you regret it
2, Did you have to put sound proofing on the firewall
3, Did you have over heating problems with the factory radiator

I have other questions but this is the most pressing right now. The reason I'm looking at the 6.2 is I don't want to hack a truck up and I would like to be able to change to a 350 in a weekend. Please post your comments either for or against. Good or bad, Lets hear it.