We see a few setups now and then that just do not make power even when there seems to be a good tune and A/F ratio. I have personally seen cars go faster putting back on a stock set of heads since the port job was so horrible.

So how often are heads made worse or sometimes just made so that they only flow up high in lift numbers. Cars need more than just the high values that everyone likes to talk about.

I know there are CNC port jobs that will likely rule out human error better. You see manufacturers making heads that do not need porting now and are set to go right out of the box. How much of this can we buy into as well.

Anyone feel like arguing some points on head porting.
What heads are truely good out of the box for the all so common 350 to 400 cubic inch range. Talking LT1/4 and gen1 engines as well. How well are the new GM fast burns compared to a set of CNC AFR's?