well this is my first post, i am not new to the forum, so far i have just been reading what other people post and faq's trying to gain knowlege. But anyway i am about to try and fab up some manifolds, as i am going through a welding class next session at school, and i want to leave with some stuff i can take advantage of. I was wondering what diameter pipes everyone is using for exhaust manifolds, and runner diameters for intake manifolds. I have seen the full race dyno before and after a lot manifold, and the results i thought were great, But i was wondering what other styles are producing these kinds of numers, or just some input on what style of manifold to do for certaint set ups. These items will be going on a midly built b16, shooting for 400+hp. Any input will be appreciated, as i am trying to gain as much knowlege as posssible for now. Thanks