Ported head question

[rccola01]

I would like to say thanks for all the good info that you have given me it has helped a lot. I'm going to pull of my heads and intake manifold I want to port them out myself b/c i herd it can be done also i have an old pair to practice first. My question is at what should I make the opening when porting them out. That is aggressive but not too much because this isn't going to be a strip car just a sunday drive around and maybe others but just for street. Need help