I can't help you with the manufacturers site, but I can tell you I recently finished converting one. I stuck a larger walbro carb I had around on it, opened up the exhuast and am getting 7200 rpm with an master air screw 16x8, I get over 8k with a 14x8. The stock horesepower rating is 1hp, I'm getting about 1.3 out of it now. I hope this helps out a little.