First I want to thank the guys that tried to answer my earlier post. I guess I did not give enough info. I would like to know about solid copper exhaust manifold gaskets. I hope somebody has some experience with them. Do they require frequent tightening? Do they work? I run a 355 with Sportsman II heads and Flowteck afterburner headers into a 2 1/2 pipes. Daily street driver. I make about 400HP.