[Tony Curcio]

Since we're just talking here, I'll add that a spec head that is CNC ported from the factory is easier to police against stealth modification. If there's any doubt about whether a head has been tampered with, the manufacturer can scan it, or run it throught the machine again.

In order to pass, it not only has hold the correct volume, but the shape must be identical as well. With CNC, there can be no arguing about how you found a "lucky casting".