All of you thinking of spending a load of money on headers need to read this months Car Craft. They bought a LS-1 they said was from a GTO and tried several headers and recorded the Hp and Torque gains. Virtually none. They said that theirs had the exhaust manifold from the vette and that if you had the one from the Camaro it was about 9 HP worse. I looked and mine is from the vette so I assume all of yours is.