Flow numbers and max HP potential

Another thing on ported heads! There is a lot of voodoo to them when your new. IMO, from what I have done, you would have to go pretty far on a ported head for it not to improve your engine but that can be an easy fence to jump. There is a mixed bag of stuff that needs to be looked at and what your doing as well. A great example of an excellent street head is the TF heads. Small ports, good velocity, this is a good power maker. If you did the same thing with another head but your port window (cross sectional area) is like a race ported big block head designed for a 528 CID engine, well, I think you get the picture on how it is is a big column of air that just won’t move the air due to a small engine of 330/360/408 inches.

There are various books on this and a few good head porters that can help explain this and perform the work.

I am not one of them.