Today I cleaned the head and block off, using brake cleaner, a rag, and a razor blade. I also mopped off the head gasket. I took the small points file to the two locating dowels, gently, so that I was just deburring it. After all this I lowered the head onto the block, stopping with it an inch or two above position and again checking for trapped gunk or lint. Then I lowered it into position. It dropped right on flat without any of the difficulty I'd had before. I suspect that deburring the locating pins was a good thing to do. I then gently snugged all the head nuts, then backed them off so that it was sitting flat but with no clamping tension on it.
Then I torqued it down again, this time in <I>four</I> stages, using my spiral pattern. First at 40#, then the given-to-me 75#, 125#, and 175#. I also oiled the studs first. The head seemed to go on easier than the last time, and the torquing was much smoother due to the oil. High hopes! After I put the rockers back on I had to set the valve lash again, they were all too tight. This implies that the head went on closer to the block this time, which is a good sign. Anyway, with the engine all reassembled I put the new propane fittings on and hooked up the tank. The motor fired right up, which was good. _Unfortunately_, the head is _still_ leaking in the middle of the exhaust manifold side. Sigh. I suppose the next step is to pull the head again and use the spray copper gasket goo. This is really getting old. -- Jim