Those are new to me.
I've used the "thick" Fel-Pro gaskets mentioned above, but like fast68plymouth mentioned, they delaminate (peel apart?) during the first disassembly.
If my standard Superformance VC gaskets have any sealing issues w/ Indy cast covers on Edelbrock Victor heads (something odd about the Victor's valve cover rail, as I recall from AndyF), then would the Carbon-X be your next suggestion?
If you have the Superformance #3186 Micropore-15 valve cover gaskets check and be sure the valve cover sealing surface is flat.
You won't have any issues.
The issue isn't whether the cast valve cover flange and the cylinder head valve cover rail are both flat (they are), but an overhanging issue like I believe AndyF brought up previously.
When I put the MP-15 gasket on the valve cover, it's a pretty good match. When I put the same gasket on the head, it overhangs the intake-side of the valve cover rail noticeably, leaving only part of the gasket to seal on the head while the outer edge is covered up by the exposed lip of the underside of the valve cover flange.
This is an Edelbrock BB Victor design eff-up, but it is what it is.
So what you are telling me is the gasket does not cover the whole flange on the cylinder head and there is exposed sealing area area?
I understand what is being said about the alignment of the valve cover flange in reference to the cylinder head flange not being in optimum alignment. If you had .125" or more of contact area where the valve cover and the cylinder head meet on the top sealing surface it should be enough to load the gasket and create a seal.
Now let's just say you only had .125" of good contact area between the valve cover and cylinder head along the top rail. If you "increase" the thickness of the gasket it will tend to roll/twist the gasket on that flange and give you the shear that Andy speaks of. More thickness and softer density will make the matter worse.
Can you set the gasket on the head, throw in some bolts for alignment and snap a pic or two of the flange area?
