Uggggh! I'm only going to say this once and I'll not argue about it. Get the open chambered heads. Open chambers flow better and you DON'T need the bump in compression.
LOL... NO obviously I'm not looking for a bump in compressions I have plenty of that. I have open chamber heads. It's just if I go to an aluminum head likely I'll end up with a closed chamber and special made Ultra thick head gaskets LOL...