Thank you all for the replies, there are some great suggestions here.

It seems the vacuum pump is the next thing to check. I’ll take a look at it today and post an update.

So far I have adjusted the valves, and in doing so confirmed that the crank turned smoothly, so at least there is no engine seizure yet.

The valves were pretty out of spec. The majority of them were tight enough that I couldn’t get the feeler between the rocker and cam, and the rest were way too loose. I agree with most of you though that this probably wouldn’t cause the grinding or the stalling.

I’ve also replaced the fuel filters and did an oil change, just to cross those off the list. The car definitely needed it, the inline prefilter was super clogged. That alone could be the stalling issue. Haven’t tried starting it yet. If the vacuum pump checks out I might just try cranking it to see what happens.

Thank you barry12345, I’ll also check the first rod bearing as well, that’s a good idea. The belt is still on the AC pump. Is it possible some bearing went out on the AC, power steering, or alternator? Might explain the grinding, not sure about the stalling.

Again, thanks to everyone for their input.