I'm unsure if the 216's head bolts extending into wator/oil galleries but all I used was oil on the threads of my 216's head bolts and so far no problems/leaks with approx. 10k miles on it.
Now my 216 pizzes oil out other locations but not through the head bolts
re. head gasket sealers, I've never used any type of sealer on a head gasket. From small air cooled to large diesels, I use the proper head gasket, clean "true" surfaces and the proper torque technique on oiled head bolts.
Dave
