Here is an animated gif file of the horsepower charts
generated from today's cut and test session. I trimmed down the aluminum
velocity stack tubes (under the blue plate in the photo above) little by
little. I re-bored the tapers into them and dyno'ed the results after each
boring. Each change in length is changing the resonant frequencies of the
velocity stack. I have numbered the harmonic peaks. It is amazing to
watch the peaks move up the graph in conjunction with each new length.