Decking Head a Must???

[ETTInnov04]

Is it really necessary to have your head and block decked to ensure proper seat of a metal headgasket? This is what I've been told. I've also seen people use that copper seal crap, and I saw the same people with leaky headgaskets. Just want your opinions. Thanks-Chris

[180fan]

Not absolutely necessary, but a good idea IF you've checked for flatness and it's out of spec. Just eyeballing isn't good enough, when I eyeballed it, it looked pretty good, but when I checked, it was actually off and then decked it to just enough.