Pontiac 400 Exhaust maifold gasket

[jasonL78]

Guys what gaskets are you using on these 400 TA manifolds. I changed them out with stock looking fel-pro and the driver side is still leaking. I removed the manifold today cleaned up the face of manifold. Using a straight edge it looks like the manifold is warped. The center port is lower than they the two outside ports. So I tried to get them square to each other. But after I installed the manifold it still is leaking on the center port. So do they make a thicker gasket for these pontiac manifolds?