I have re-worked 1961 390 Hi-Po heads and used Felpro 1442 composition gaskets with no problems. I first tried SEC copper gaskets (have 3 sets hanging in the garage
) but I had problems with them. I eventually traced the problem to a header bolt washer trapped between the block and header flange (my fault) but I also noticed there was a minute leak at every port along the raised bead. My advice would be get the Felpro gaskets and be done with it.
You do have to be careful with header gaskets on FEs as I think there are at least 4 different port height/bolt layout variations. The SCE # was 4034 for my early FE heads.