Just spent over an hour changing out the composite gaskets that came with my Hedman Elites to copper embossed gaskets. Went from 1 small leak on 1 side to 2 large leaks on both sides!! Great!

try torquing from the inside out a lil at a time and if you over tighten and bend the flange the copper will remind you of this .. i have had good luck with those alum layered gaskets on headders. havent had a leak since i used them at 40 a pop im happy . might try them

They're great! My experience has been to use the round hole version as opposed to the square.The round tube header did not seal well with the square hole gasket so I went back to the round hole gasket.As a little insurance I used a bead of high temp orange silicon sealant front and back of the gasket.Don't glob the sealant on but just a fine smooth coating. No leaks and you can use them over again.Worked for me should work for you too.

Big 10-4 to Motown Malibu. Center out a little at a time and once your bolts are tight warm those tubes up and tork em again.

I've had good luck with paper gaskets that come with the headers, Mr.Gasket paper gaskets and I'm now trying stock exhaust manifold gaskets on the new motor, so far so good,but doesnt have many miles on it yet. I always tighten the bolts when cold,,,take it for a spin,,tighten again and after one more drive,check again, I've never had them come loose either.