Okay heres what gets me.......you dont want any back pressure, correct? Well if thats true then why is 3" exh too big for a naturally aspirated engine? Like running open header, no back pressure and more power, but with 2.5' exh and 3" exh the 2.5" is considered better....why?
Will some knowlegable person(Mrfatbooty for ex.) please help me answer this question?



Thanks alot
-Chase