I am changing my exhaust system to SS. Of course I snapped off the flange studs requiring me to remove the manifold and take to a shop to have studs removed-duh! I have a new gasket. It appears to have a different profile on each side; one flat and one kind of 'puffed'? Could anyone tell me which side goes to the head and which side to the manifold? Should I use any kind of sealer? There doesn't appear to be any there from the first time and it sealed quite well. Thank you.