Grubdigger, would you use a stock exhaust or build a header. If I built a header, is their a formula to figure approx size and length? Dont want to build a header that sounds good, but robs me of engine performance. Thanks in advance for any advise....... I think that the stock exhaust can only has a 3/4 or maybe 1" exit header into a silencer can. I would have to imagine that a new straight pipe would allow more air flow.......