My cobra has one piece exhaust from tip to head flange, but if I had a flat flange exhaust joint to seal; here's what I'd do...
I'd call these guys
http://www.byson.com/diecut.html
Why?
- They built several sets of custom header gaskets for me for a song; just for the opportunity of filling a niche that wasn't filled. (Chevy exhaust blue thunder, supercharged application, 1600deg F capable)
- They build the gaskets from a CAD drawing I provided.
- They use GOOD materials; including ASBESTOS laden polymer impregnated fiberglass fabrics that hold up to the abuse that such a flange will see.
- They know their business; they do race exhaust for very demanding applications.
I'd call them up, tell them there's a need for bulletproof gaskets in this application, send them a sample, and they'll help you build a gasket that will last forever. Hell, they may even make it already. If it's a problem gasket, there's a good chance they do.
Byron Reynolds
RACE Systems
San Jose, CA