Horsepower figures, like gas mileage figures, are generally calculated with a pencil and a large imagination.. What's important is, my 41 spins the prop at 7200rpm, flys the plane very well, and is dependable as sunrise. It took about three gallon of fuel to settle the break in..
The B&B muffler, and the WA#144 carb mods were about $50 bucks, and i feel they were worth it, just simple bolt on changes that brought the engine price to $325.00.. It is NOT one of the alphabet engines,but it doesn't cost $5-$600 either....