Thank you all for the great input. Lots of good advice so far.

So far what I’ve done is the valve adjustment, fuel filter change (both inline and main filter), and oil change. No actual engine diagnostics or anything like that yet.

The valves were fairly out of spec. Most of them I couldn’t even fit the feeler between the cam and rocker, and all were out of adjustment somewhat. Still I agree with you all that this shouldn’t be the reason for the knocking/grinding and stall.

The vacuum pump is a great idea, I’ll check that out today and report what I find. Thanks also to barry for the first rod bearing, I’ll try to take a look at that as well.

Could a bad bearing in some fanbelt component be making the sound? AC compressor, alternator, etc? If so how would I check that? Just turn each component manually and listen?