my gasket between my manifold and up pipe blew so i replaced it with a genuine subaru one only to find it wasnt sealing the exhaust tryed everything paste gum gum wrap the heap only to find that it was the wrong gasket it fits the manifold side perfect but the up pipe side the ring of the gasket isnt actualy touching anything the up pipe is bigger diamiter than the manifold is there a special gasket for this and where would i find one cheers