Installed CI headers and thrush turbo mufflers, ran dual exhaust out in front of rear tires, sounds great!! But took it on 2 mile stretch of highway and ALL she had was 65mph on level ground!! Stock manifold and single exhaust I could hit 75 if I wanted to, always held her below 70 for safety reasons. Also I keep blowing exhaust manifold gaskets between 3-4 exhaust ports, will the Clifford wedge help with that? Or is it a matter of manifold vs header mating surface? Thanks