14 high end 3.5cc rc engines in paralell = 49cc, will get you past 40hp.

How many HP does a 50cc engine have?

50cc Motorcycles:

Lightweight motorcycles with 50cc usually have 2-stroke engines that produce anywhere from 3 to 9 HP. However, some racing 50cc motorcycles can pack a punch, getting up to 15,000 rpm, with anywhere from 10 to 20 HP.

How many horsepower is a 49cc 4 stroke engine?

At approximately 2.5 HP this bicycle engine gets about 100 to 150 mpg and can hits speeds of 35 MPH or more. 4 cycle engines require little maintenance. Simply add gas and oil and the engine is ready to operate.