By Decking or Milling the head that much your not gonna get that much hp out of it, especially on an engine as old as yours is. Its not gonna be worth the effort. Just do an engine swap if your gonna spend that kind of $$ to get that little hp out of it. I agree with westcoaststyle, you can get 3CR points out of pistions with less effort than having to mill or deck the head and worry about the valves hitting the pistons, and the engine could use a rebuild im sure.