The new intake valve angle of the Trick Flow heads eliminates the piston-to-valve interference problems, now allowing guys to run cams with valve lift to 0.600 inch. It also improves airflow from the intake manifold to the valve. You can buy these heads from Summit Racing for $997.95 each, and Clochiatti and Modular Head Shop's McKinney both say that out of the box, the Trick Flow heads outflow any safely ported factory 2V heads. If there is a downside to all this extra airflow, it's that most naturally aspirated street engines may not be able to take advantage of it. The Trick Flow heads may be better suited to forced induction or stroker builds.