Pulling apart an AAZ yesterday and I found out why the previous owner said "it just stopped running". Crank bolt had come loose. Pulled the head and expected to see the usual, instead I met the luckyest pistons in the world. The valve imprints don't even go as deep as the dishing.

This is normally what I see when there is a crank problem (the bolt sheared on this engine), minus the rust!

The head is in great shape from the first picture, better than I usally see. Too bad about the crank bolt!
Ian