Header gaskets aren't supposed to reusable, but you can sometimes get away with it...
Just don't over-tighten to correct an air leak.. if you have a leak at proper tension,.. buy a new gasket...
I bought a new one and left the old one in place.. double gasket ensures that you don't bottom out on the bolts before reaching snug...
Not saying that's the right thing to do,... it's just what I did...
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