Streetmaster to Airgap

So take a fully engineered race engine designed to be legal in a certain class and put mediocre stock heads on it in a fully engineered race car and make enough power to go high 11s. Take the same engine and put on some ootb speedmaster heads on it and drop a half second at least. Why use the stock heads?, only if you have to for class racing.
Poor flowing heads will make SOME power on a race engine, good flowing heads will make GOOD power on ANY engine.