Sorry Chris,
My mistake, I thought he said cast manifold. And since he did I was going to suggest looking at this intricit and scarey litttle Mazda engine. Cast Aluminmum Manifold and motorcylce and some marine engines have them too. Hmmmm. See this whole Mustang being built in a Mazda plant just makes me wonder......
http://www.323gt-r.com/spec/engine.html
Jenn