Originally Posted by spittoon
quick question, do you HAVE to tap out larger holes in the head or can I use the current, smaller-sized bolts?
If you are referencing a smaller hole that is already threaded use it instead.
Some heads will have holes threaded and smaller helicoils inserted into them, while others will only have indexing holes, those are rather shallow but I've read that tapping them without drilling deeper has been successful.
Point is there are several different head treatments, your application may vary.
While the "gorilla snot" sounds very effective I've always used Indian Head gasket shellac, gluing the gasket to the valve cover. IMHO using a silicone sealer is a