Well, I ordered a Jett Sport Jett 40 with a Super Sport 40 muffler. Dub said this would give me power equal to the 46 and on a good day, close to the 50 while being very close to legal to race with, I would only need a different carb. Dub was VERY helpful and took the time to find out what I wanted/needed and to give me a solution that would fit those needs. If this engine is anywhere close to what people say about them, I may be hooked on Jetts for life. Great company and excellent customer service.