We had a little problem with the software on the dyno and I lost some confidence in the results which in the end were 4 hp gain. So I went to the track and ran the same times more or less. I think I was a few hundredths of a second faster. Around 4 hp faster. We did a before dyno, an open header dyno and lastly one hooked up to the stock resonator/muffler. The 4 hp number is the difference from no cats and stock exhaust; then headers and stock afterwards.

Les