What exactly are o-ring heads? I have heard this term a lot lately. Does the block have to be grooved too? What kind of gaskets do you use? Is it expensive to have heads o-ringed?

 

Unless you're planning on running a lot of boost, don't bother. IIRC a groove is put on either the head or the block, then a piece of wire (o ring) is put in it, then the gasket goes on, and a groove is matched on the other side for the ring to mash the gasket into.
Don't they usually use copper gaskets for o-ring applications?

I'm really not sure, but it's something that most of us shouldn't bother with.

 

o-ringing is for supercharger or turbo applications were the cylinder pressure is great. it is a thin copper wire usually put into a groove in the head because in testing it is seen that it is actually the head trying to seperate from the block which causes the failure. unless you are running a forced induction application you dont need to bother with o-ringing.