I bought my '83 GMC diesel conversion van 7 years ago for $3000. It now has 320,000 miles on it, and needs a new motor, and I'm having trouble convincing myself that I should buy a different vehicle, rather that rebuild the motor. The diesel conversion van has everything I think I would ever need, except four wheel drive. I don't yet own a drift boat, so this isn't a big deal, I've never gotten stuck at the boat ramp, nor have I ever gotten stuck while up in the mountains snowboarding... though I use chains up there.

I don't know how much torque or horsepower the 6.2L engine puts out, I just know that with 320,000 miles on it, it still pulls my 19' Custom Weld sled no problem. I get about 19mpg, and could do better if I changed the rear end gearing. Check out this site, it has lots of good info on GMC diesels:
http://www.62-65-dieselpage.com/

It also has an excellent article on diesels and fuel economy here:
http://www.62-65-dieselpage.com/mileage.htm

Diesel conversion vans are pretty rare (don't know why?) but if you can find one, buy it... mine's got room for all the kids, all the gear, will tow the boat, when you're tired you can pull over and sleep on the queen sized bed in the back... it's awesome.

P.S. If you can find one with a 6.5L or 6.5 turbo, those are supposed to be much better engines than the 6.2L

-N.