HI Ric, yes I did, but you must realize that it is a combination of all four items. I will really see more gains when I change the cam. In order for the scavenging effect of the headers to truly work you need overlap on the cam lobes. Both intake and exhaust should be open similtainiously at the end of the stroke, this allows the pressure created by the explosion to not only evacuate the cylinder but suck the new mixture in as well. The smog cams we get on the stock engine are ok but have very little overlap. Hope I didn't go to astray from your question.
03 H2
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03 H2
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