I owned a set of w9's and had them flowed by crower. Out of the box, unported the W9 flowed pretty much the same as a trick flow head. What the flow bench doesnt show is how much more power the W9 raised port will make over the entire flow curve. If i could have found the same deal 67 autocross did my 340 would be wearing W9's instead of W2's. They are an incredible head. Another Mopar Performance marketing failure.