Not sure yet man. I didn't know there were different kinds of portings. I saw a thing that explains it in my big block chevy books and I haven't gotten to that chapter yet but when I do I will be taking lots of notes, and then practice. I will for sure get pics. When I get real good at it then I will do my 302 heads on the Ford and then later when the 454 is built on the 48 I will do them too. I won't do it unless I know how to do it really good without worrying about messing up.