Just a few points, the Chevy 350 is probably one of the best engines
ever built. These engines last many years in marine applications. Their
are very few other gas engines that you can say the same thing about.
They were easy to get parts for, and even heavy duty parts were cheap,
they were simple to build or repair. They weren't perfect, but they
were very reliable, and took a beating.

Diesel oils are made to handle sulfur which is a main concern when it
comes to blow by, they are also formulated to keep contaminates in
suspension, so it comes out with the oil when you change it. That dirt
in the oil is not dirt left in the engine. When you switched your
little Honda over to synthetic you saw what you should expect to see,
dirt in suspension being removed from the engine. Synthetic oil holds
contaminates in suspension better than standard oil, after a few
changes the engine starts to clean itself out, and the oil looks better
when you drain it. By the way, diesel manufacturers are testing their
engines with synthetic oils. I'm sure they'll work just fine, the
problem will be cost, with synthetic their probably looking at about
$50 to $100 worth of synthetic vs $15 to $30 or so of standard oil.

When you talk about overhauls on trucks, they don't run the engines
until they die, and overhaul them. They run them to some point, pull
the engine, and overhaul it, or install another one that has been
overhauled and overhaul the one they just pulled. Their in the business
of hauling freight on time, waiting for a breakdown in the middle of
nowhere doesn't work for them.

Gen sets and long haul engines last a long time because their running
most of the time at constant speeds and loads, it's the start and stop
kind of operation that kills the engine.

And Rotella, Velo and Delo all come out as black as night from a
diesel, even on new engines.