Exhaust Flange Gasket Required?

[Sharps40]

When I used the walker head pipe on my I6, the walker head pipe came with the tulip shape to the end. Looks like the pictures in post 8 above. Basically, the tulip shape eliminates the need for a doughnut gasket to seal the pipe.

Slipped the manifold ring over it, clamped down the two nuts on the manifold and perfect seal....no doughnut required. If your head pipe has no tulip shape, it probably needs the doughnut to seal up.