The Stovebolt Site Forums The Shop Area Engine Shop 216 Exhaust manifold leak

I recently removed the head on my 216 to have it checked for cracks (none were found). I put everything back together with new gaskets, gasket sealer, and the proper torque for the head and manifold bolts. About a month later it developed an exhaust manifold leak. When I checked, many of the manifold bolts were pretty loose, so I tightened them back up. This worked for a few days, but now I can hear a leak when I first start it up. After the engine warms up, the leak stops. The manifold bolts all seem tight. I did not have a problem with exhaust leaks before I took the head off (the machine shop milled 6/1000 off the head, if that matters).
I'm wondering if I have to replace the gaskets once they start leaking.

Most exhaust leaks are a result of a warped mounting surface. I think the gaskets are quite forgiving if the surface is flat. The fact that the leak seems to end when the engine is warm is telling me that the gaskets are serviceable.