It is great to just hit a switch and after about 30 seconds for the line to clear I have another 100Hp on tap over the 463 normal. The exhaust port is just fine, I might run a felt cone over it with some compound to smooth it out. The intake is choked off a bit at the top of the valve pocket and the port at the head is a bit small. The carb is small by all comments I have read, and lean running for emissions reasons. I do have some carbs from 36 and 49cc skateboard and scooter engines laying around that I might try but I read a promising post about a fellow who says he bored out the stock jet and got gains each pass, then removed it all together from the housing and solved the lean condition accros the RPM band. I want to give this a try. Once I get it mounted and running I will tach it with the various changes.