There's two schools of thought that I have encountered when it comes to the subject of cylinder head lifting.
Both approaches are just as valid as the other.
One is to allow the head to lift, and choose a sealing mechanism that will cope with the clearance created between the head and the block when the head lifts.
Whe the head lifts, it usually "bows" in between the studs, and the point of maximum lift/deflection occurs at the midpoint between the head fasteners. So some people oring the head and reciever groove the block/liner and use a copper gasket. This works well to a point. Some use a standard gasket and machine a large, squared groove into the deck of both the block and the head, and fit a closely machined ring of copper into the groove. The ring is a rectangular cross section, and fits deeply into the block and the head. The standrad gasket is cut out to fit around these rings, and is used to seal water only. This method works great, but is difficult to machine and, from what I hear, is nearly impossible to disassemble once the engine has seen some high boost cycles. Another method is the one Marty used and he touched on it in the other thread, and that's the gas filled oring/sealing ring. The ring is compressed slightly in its groove as the head is torqued, and if the head lifts the ring expands to take up the gap. Also, as the hot combusion gases come into contact with the ring, the pressure in the ring increases, which tightens the seal further. This is a great method to use if you have room between the cylinders for the rings, which most engnes do, but some don't.
The other train of thought is to do everything humanly possible to keep the head from lifting to begin with. This usually entails a billet cylinder head, large head studs in greater than factory numbers, or cylinder head braces, in the case of some factory aluminum castings used for racing. Tractor pullers have some rather ingenious methods of keeping everything sealed up, but to keep from getting death threats, I won't post those here. They are far to heavy for our uses in drag racing, anyway, and involve quite a bit of tricky machine work to the block and head.
That's what little I know on the subject. I know that Rodney and I have found the sweet spot for keeping our E-heads sealed up, and that has greatly minimized our head lifting/gasket sealing issues. With alcohol for fuel, if you lift the head much at all, you torch the head and block, no exceptions. So it's pretty imperative to keep them down!
TQ
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