863, was a beast, when she came out first complaints where fuel consumption. (more power more fuel) next was oil consumption. quart a week was normal. ( verified by a service bulletin)., than guys started breaking chains, (over the tire tracks ) made it worse, owner operators learned how far to push, as well as how to replace chains.!! blown head gaskets were common, but thats all it was. a head gasket. (timing bellt checks very important) yet if it goes not a big deal rods designed to bend an adsorb damage, ( S rods) a suspension seat is a must, i put hundreds in,