Copper Header flange gaskets

https://www.amazon.com/Percy-66037-Seal-4-Good-Flange-Gasket/dp/B000NCY6NM?tag=fabo03-20

I used these, always remember to retighten them a few times when warm, but I've had a set of these on the Duster for 11 years with no leaks with my TTI headers.