I got an 89 dodge 1 ton 2wd. In january issue of dieselpower there's a complete article on modifying first gens. in that article they mention that early first gens (89 to 91 1/2) are not intercooled and have the 3 spd auto, not overdrive. But they do have bigger injectors than the later models and the 3.07 axle gears. The later models (91 1/2 to 93) are intercooled and have overdrive transmissions. Figured it would be easy and cheap to find a junk later model and swap in the intercooler and plumming, and the transmission and get a 25+ mpg truck. I looked around and may have found a family friend with an old 92 i think just like mine, but with the intercooler and everything. Any hints advice or more information on the differences between these amazing trucks?