i havnt been able to find if theres a thread on this or not, so if there is give me a link and delete this post, what is the difference between a 4-2-1 header and a 4-1 header, im not looking for track use but more for street and need some info, like i said sorry if this question has been asked..gotta start somewhere ya know?

 

I'm no expert on the subject but I assume the performance differences are mainly in what RPM range each ones makes the biggest gains. IIRC, 4-2-1s make more power in the mid range while a 4-1 makes more top end power.