As you mentioned, chain guide or lifter nest/holder if it is plastic, and they both have been known to break. Now is probably a good time to start surgery. If you are yanking the engine, it will be easier to work on a stand, but as mentioned before, the in car route ain't to bad either. I would also add to the list of to do's-- remove oil pan and clean along with pickup. Please continue updating


Edit: im curious what the valve covers are hiding- that pic almost looks like sludge accumulate