Valve cover gasket: cork or rubber?

Looks like the 225cid slant six in my recently acquired '64 Valiant is leaking some oil. I discovered the bolts were very, very loose. Have tried to snug them down a bit but oil still seems to be leaking out. So am considering replacing the gasket. Fel-Pro makes two kinds of valve cover gasket for my car, cork or rubber. Is one better than the other? Is one easier to install? Which should I go with? Or is it six of one and a half dozen of the other?

Any ideas?


Glenn