Ringleader, I too believe finish is as important or more so then flatness of a deck. With out the grip of machine marks, the gasket has nothing to hold on to. You have a much better chance of sealing a slightly rough finish, then a glass smooth surface. Perfectly flat surfaces are different then smooth surfaces, but due to the nature of a engine block and head surface, getting one dead flat is pretty tough.
I would also bet that copper was a left over design from years earlier and a quality fiber gasket were still in the future, so a combination of material was used.
I had the chance to use some NOS 1970 Pontiac head gaskets on a 455 a while back. They had steel on the block side and fiber on the head side. Directions said to spray the steel side with Copper coat to "heavy consistence film". Even with that, they were seeping after a 1000 miles. I replaced them with Felpro standard blue gaskets and problem went away.
Joe
