You screw the head onto the cylinder, and if it is off alignment at "tight",
there is an allowable amount of "back me off" angular adjustment that is
allowable to make the intake/exhaust ports line up.

In the field, big and long wooden dowels stuffed into the intake/exhaust
ports and smartly pushed and pulled around to make the sucker line up are
not exactly in accordance with the service manual, but is how it is done.

Of course, such an unapproved procedure would NEVER be used by a reputable
mechanic, but ....


Jim




"Cy Galley" wrote in message
news:bBK%d.93211$Ze3.82701@attbi_s51...
The Cylinder head is screwed on the cylinder like a big jar lid. I always
though that they used the old head with a new barrel, screwed it on tight,
then jig drilled the mounting holes is the flange of the barrel. I don't
know how one would index a new head with and old barrel. I suppose it
could be done with shim gaskets, but if you didn't get the right shim, the
head would not stop at the right place.