Just another chiming in on using no gaskets between the head and exhaust manifold or header...Heat shield? maybe, but no gaskets.
Get the head mating surface flat and true.
Get the header mating surface flat and true.
Get both surfaces very clean.
Use a thin film of Ultra Copper, or similar high temp sealer.
Bolt things together and for the firts few heat cycles recheck bolt tightness...Done until you choose to take things apart.
Getting the header flange trued up sometimes takes effort and time because you have to weld up and grind off material to get a good finished flange.
In the end, specially considering what it takes to redo the header gaskets, the time and money spent getting the flanges right is well spent in the long run.