[MylilBowTie]

yes it seals the header to the rest of the exhaust without a gasket. But it has to be welded into the system. The header collector flange on the header needs to be cut off and part of the flange ball welded up to the header. Then the other part of the flange ball setup gets welded to the exhaust pipe system. Its a much better design to seal that area. Most Fox body mustangs have that setup factory as well as most newer cars.