[Walt Fricke]

Otter:
The picture, as posted, is backward. If you flip it horizontally, it will look like what your eye would see if you were a rubber pinhead and could get in there and look directly (or had it on an engine stand). #6 is right next to the top of the oil cooler, which you can see in the snap shot.

The cylinder head has two drillings through the fins. The lower one, which is a straight shot in, is where the head stud is, with its round 10mm stud barrel nut - the things you tried to retorque/test and some confusion arose.

The second drilling is right above it, and is for the spark plug. The spark plug is not a straight shot. It angles up and to the rear some - that's the angle you have to set your spark plug wrench when R&Ring a plug on the right bank (up and forward on the left bank). If you pull the #1 plug and look in there (where you can stick your head), you will see the layout.

So my guess is that you have a fine photo of a head stud barrel nut.