The shortest distance between two points is what? A straight line. Airflow wants to take the shortest path from point "A" to point "B", and if you look at the FE intake port, what is the shortest point from the gasket to valve seat? The air wants to go to the short turn next to the exhaust valve . That reduces flow, creates turbulence, and loss of power. A porter should try to direct the airflow so that it stays up in the port, and exits over the whole valve face, not shear across the short turn side of the valve. Those vanes in the TFS heads do that quite well. If you take the intake valve out of the TFS head, you will see the bowl is not round like other heads, but has a huge directional wall that helps with directing the airflow into the combustion chamber. Reminiscent of the first LS heads with their swirl channel built into the port. By keeping the ports small, it forces the airflow to stay in suspension, and not shear like most FE heads do when the airflow gets very fast in the ports. Short turn work is critical in keeping a FE head airflow increasing with valve lift. Joe-JDC