I understand these tiny single hairline cracks at the
shortest distance between intake and exhaust valve are
common.  Does this mean you go to the machinist and
pay $200??  I guess I should get the head leak tested,
at least.  This is an '86 westy and I am doing the
heads engine in as the corrosion pits finally got to
the gasket.  I was planning on doing the J-B Weld fix
till I saw the cracks.  Compression was 145 on #'s 2-4
and 130 on #1.  Not bad for 160,000!  I will attest
that the best way to free the cylinders from the head
is the open-end wrench prying on the cylinder ears.
Works like a charm.