Yeah... probably not gonna happen... GM tried that with the 350 or something... didn;t turn out well at all!
The International 6.9/7.3 is a converted gas motor if you want to look at it that way. They did it the same way as GM did--use the basic design of the gasser, but re-design everything. Neither actually converted a gasoline engine to run on diesel fuel. The International guys got it right. The GM guys got it pretty nearly right, but I think it was GM corporate that made the engine fail--even though they sold over a million of them. In 1978 there was no distribution for diesel fuel for passenger vehicles. The average person was duped into thinking owning a luxury diesel-powered car was the same as a gas car--just fill it up and drive. GM didn't even have a water seperator installed, and with a half-assed fuel distribution, given the fact that diesel and water are similar weights, pumping water into your tank was a common problem. The other problems with the engines (there were 3--a 350 V8, a 260 V8, a 260 V6) were easily correctable, and in the case of the V6, was a good engine. Rushing to production in an effort to get the drop on the other manufacturers caused things to be built before being adequately tested and the problems shaken out.
The 6.2 wasn't really the cure for the Olds-based diesel, it was designed from ground up for trucks. It was in service for 4 years alongside the Olds engine. The Olds-based diesel engine was offered in 1/2-ton 2wd trucks for a couple of years, actually. To GM's credit, they had the balls to build full-size cars with diesel engines, and they built and sold a lot of them--over a million. The one-millionth Cummins-powered Ram rolled off the line last year.
The 6.2/6.5 is a good choice for a Ranger because it is cheap, still in production after 30 years, accepts any GM transmission, weighs a manageable 760#, and responds well to turbocharging. You can install a 150hp $500 6.2 pulled from an Army Humvee off of EBay, and later, when your finances improve...the sky is the limit.
Check out Bobby's installation.
http://www.therangerstation.com/forums/showthread.php?t=35931