Typically the crush zone of the gasket is inside of the ZZP flange and does not get crushed, which is why you don't seal. Take your current gasket and a tube of copper RTV. Wipe your current gasket off with brake clean (if it's metal) and goop the heck out of one side. Put that side against the manifold. Now reach down and goop the hell out of the other side with your finger. Put downpipe in place and torque down. Give it 45 minutes to setup and cure.