Feral
Wouldn't there be a galvanic reaction [electrolosis] problem using a 100% copper head gasket? I know that the use of the correct coolant will reduce the problem, & in race engines, the teardown rate allows frequent monotoring, but in a street engine, i would wory that the head would become the sacrificial anode in short order.

I remember that we had problems with our flathead Fords & copper asbestos gaskets under factory alloy heads with pure water as coolant many years ago.
In fact Ford supplied a special gasket for the alloy head models.
Chris