Had the cylinder head at the local machine shop having the top skimmed since it was pretty out of whack and it's part of my attempt to stem the flow of oil between the head and rocker cover...

While there, I got a tour of the place as they also produce specialised piston rings for engines in Oz, UK, US, and Canada. This one is either for a locomotive engine or a generator.. It weighed only slightly less than the cylinder head (!)