No...thank you....that is the point I have been trying to illustrate all along.......that is based on your comment that my heads need to have MCA dimension 'A' or they cannot flow what they do.....I am trying to illustrate these theories are guidelines not rules....YOU said they are not theories they are proven...now you are saying that I am the one claiming these are concrete because of how I believe air flows on a flowbench.....I am simply saying that just because YOU need a 3.74MCA does not mean I do...you said they cannot flow 470 unless they have that dimension.....