There a guy that put a Mercedes diesel in an Astro van, the thread is on this site. I think he went with a 5 cyl turbo engine after using the 240. Go with the 95 or 94, s-10 and don't worry about emission testing. The same laws are here in Illinois, they test only ODB2, 96 or later. I was just looking at s-10 rear axle ratios yesterday using an 2.14 axle ratio and a .73 5th gear the engine would turn at 1300 rpm at 65, a little slow, maybe a 2.53 ratio or 2.73 would be better.
http://www.sierragear.com/gm-rpo-axl...ation-codes-3/
http://ecomodder.com/forum/showthrea...sel-26437.html