[quote author=danielj link=topic=136663.msg2945691#msg2945691 date=1234995903]
I don't know why you would want to bother. The stock exhaust is so restrictive. If you're upgrading the header, why not follow through with a free flowing exhaust.
lc gained ~5whp, and more interesting, 10ft-lbs with a 4-1 header and the stock exhaust. Link.
I wouldn't do it unless intending to get an exhaust eventually, but a header can work with the stock exhaust.
i had a header on my stock exhaust for a little bit. It felt nice and torquey but i didn't gain much power till i got my exhaust. I lost some torque but gained mid-top end. I had 2.5 exhaust before and now i got 2.25 with header. The 2.25 exhaust was deff a better move, a big big improvement. I noticed a huge change coming from the 2.5 to 2.25.
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