Given the core shift issues that the factory heads have, wouldn't a CNC ported set tend to be even more crack prone? Going fast w/ stock stuff is cool and all, but at some point it becomes even more of a money pit than racing already is.
Probably just the opposite. Most CNC programs are set up on the safe side so they can move product in and out the door. Most hand porters can take a CNC'd head and make vast improvements in flow. I have never had a set of CNC'd heads leave my shop that weren't better and I'm not talking about a few cfm but then again I love playing on the flowbench.
