Always somebody to remind you of the ONE thing you forgot to do.... ;-)...
I already found silver dust in the oil when I changed the old runny mess, so major surgery may be a foregone conclusion.
Look at the bright side. With the "silver dust" in the oil, it will make the decision to do a complete teardown, thorough cleaning and replacement of most moving parts an easy decision. Its pricey, but the feeling of having a brand new Stovebolt engine in your truck is priceless.