another header leak

You might want to try the ROL header gaskets. They are graphite faced and good up to 2100*, steel cored and reuseable. We run them on both our race cars and have had no problems. One thing we do is, run a bead of high temp RTV around the openings and let it tack up before installing and torquing them. We then let them cure for 24 hours and then retorque them before firing the cars up. Just a thought for you, I hope it helps.