I suspect the 6 that I found were removed from the stuff I (or the previous owner) did take apart, and there are 8 more new ones for other stuff I didn't remove, like EGR and water passages and such from the intake manifold. The set also has 8 more smaller and fatter o-rings, I suspect these are for the injectors. The spark plug galleys don't have o-rings, their seals are part of the valve cover gasket. These are also too small for that, they're only about 1/2"/13mm OD and probably 10 or 11mm ID, most spark plugs are an M14 thread and take either a 5/8" or 13/16" socket.