I think the bolt backed out, because I found it in the oil pan. It was in that first picture.

I bought a lower mileage engine that had all new thermostat, oil pump, breather box, front seals, rear seal, t-belt, dist cap, rotor, ... Since I didn't know what other havoc had been caused, and replacing all those things would have been pretty time consuming on that engine. Also I would have had to done headgasket and whatever machining the head that goes with it. And who knows, I may have gotten all that done and still found a problem with other cylinders. I could have gone the cheap route and made some quick money on the car, but at the time I wanted to do it right and have a reliable car for myself.

-Nathan