which 3'' exhaust do i want?

11.2 said
Ive had this ''to big of exhaust'' discussion before and don't get it. the first thing everyone does at the track is run open headers ''less restriction/ back pressure]. nobody has came up with a good enough theory to convince me, maybe i'll get some enlightenment here since there is a lot of experience on these forums.

I had a hard time with it too. Everyone thinks bigger MUST be better. The way you can over-carb an engine, you can have too little back pressure too. That's why professional engine builders tune an engine to primary tube length and diameter. There's some science involved relating to creating pressure pulses and scavenging. All I know is it's going to hurt performance unless your moving a HUGE amount of air through the engine going with 3".

I came *THIS CLOSE* to putting a 3" system in my car, but was told that with my cam, compression, heads, carbs... I'd be better off with 2.5".

Hope this helps.