I see jetting mentioned all the time. Simple jetting is not, has never been, and will never be the difference in horsepower. Carb throat size, reed block configurations, cylinder porting, timing/throttle configuriations, exhaust tuning, induction method, gear ratios. Some to all of those account for different horsepowers from the same bore and stroke.
no, a jet drive, do to slippage, and lack of effieceny, losses 40 % of the engines out put, compared to propped motors. a 30 hp jet might be close to a 20 hp propped.
