Re: Do slant heads really make a difference in power?
I have installed a few dozen old style engines and several slant heads. I've also updated a few of the old ones with Zoom slant heads. The difference is not placebo effect. Most of the "upgrades" claimed on this forum are but not the slant and not the SBP pipe. They both added a couple MPH on "dyno-hill'. Also low-end acceleration.
The difference in compression shows up as a major increase in starting resistance. A couple of the people I did bikes for who did not weigh much had to go back to non-slant to keep the rear wheel from skiding,