Originally posted by MAW

Stay away from the mid 80's GM 5.7L diesels as these were a POS.
Actually, the 350N motors werent bad motors once they worked the bugs out of them. The problems were associated with the cranks and camshafts on the earlier motors. Get an 82-later and youll find good cranks and roller cams. However, there are also 4.3L incarnation of these motors that are found across the GM line. Not too familiar with them, but their good for somewhere around 35mpg highway. As for Hp from a diesel, a lot of rules apply from gas motors. larger valves, free flowing exhaust, ported intake, these all work. Finally, beware of head gaskets and ALWAYS replace the head bolts if you blow a gasket. better yet, put in head studs.