This is the engine discussed in my "A65 forensics" thread. It's a fresh engine, torn down because it was making a funny clicking noise, which I suspected was detonation. We didn't find anything clearly wrong, except that the head gasket bore holes were a tad smaller than the bores. We also noticed some staining on the head mating surface, and a lot of soot on the exhaust side of the head.
Now I'm attempting to resurface the head on sandpaper. I've scrubbed quite a bit, but I haven't yet reached the center between the combustion chambers. I'm getting closer though, so I'll keep going. I believe now the discoloration is from over-rich exhaust gases.
Question: I noticed that the mating surface toward the front of the cylinder head is damn near flush with the bottom cooling fin, whereas in the back the mating surface is raised a good 1/16" from the cooling fin. Is this normal? To my knowledge, this head has never been skimmed (as by machine).