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.
