Bob,
I can answer for the port dividers, atleast my take on them. They worked well for me. I run a turbo system with multiport EFI. With them idle quality went way up and so did performance. It is more of a Multiport EFI thing, not so much for Carb.
You are also correct about variables with head work. But I have found for the average Joe, doing the same mods to a open chamber vs a "194" head, the open chamber wins.
Last I knew with Mike Kirby, he mainly reworks open chamber heads. Maybe someone should call him and get his 2 cents.
