I found my 18" Starrett rule and my feeler gauges.  I wiped down the
head and block and went looking for warpage.  Using the 0.004" gauge
(limit is supposedly 0.006") I walked all over the head, both
directions, and nowhere did the feeler even begin to come close to
fitting under the rule.  Ditto the block.

I next calipered the head gasket, which is 0.068" thick.  The old
gasket is about 0.070" thick, less of a difference than I thought
based upon handling them.

Next I placed the head on the block sans gasket.  I had some real
trouble getting it to sit flat, it looked like there was some
interference from the locating dowel pins.  I was able to use three
head nuts to pull it down on that (away from the pushrods) side, then
I removed the nuts.  It looked pretty good by eye, and probing all
around it with my 0.004" gauge it only wanted to nose in a bit in some
places, and only slipped in at one corner of #1, which is not one of
the places I was seeing leaks.

Looking at all the studs I found no place where there were
insufficient threads protruding.  So _that's_ not it.

So, from yesterday's list I'm only left with surface roughness as a
potential culprit, and that seems unlikely to be responsible for such
widespread leaking, especially as the gasket is a rubberized (?) one.
It seems pretty grippy, unlike the old 2-layer metal one.

Sigh, no real smoking guns.  I suppose it is possible that the
business with the dowel pins could have been responsible.  If the head
got started clamping down while it was not seated flat to begin with
it could have gotten 'trapped' at a bad angle and leaked, even though
it looked OK by eye.

The current plan is to put it back on again but this time paying more
attention to getting it flat before I start torquing the nuts down.
If it leaks again the plan is to remove the head and use that spray-on
copper gasket sealant I bought yesterday.  If _that_ doesn't work
I'm not sure what I will do.

-- Jim

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