The plugs are all in the correct positions. As aforementioned, nothing was touched under the hood when all of this began. Since then I replaced the rear header gasket which was probably fine, and the valve cover gasket, which was faulty. That eliminated the black smoke.
I cleaned up the engine and took a video as instructed. It's in the same file repository here.
The place where I'm waving my hand is where there's a light wispy smoke that looks like it might be the gas vapor but can't tell where it's coming from. If you see puddles of water, they're just that, from the engine cleaning. I couldn't fully dry it with the blower.
