RE: 428 motors
and only with a 9/6 apc prop. There is some flexibility though. A few areas in the US use the OS46 with 10/6 props. But as you can see there has really no comparison been made. The TT40 selection is based on under $100 price and good consistency from unit to unit. The magnum is not in the mix because of poor performance consistency from unit to unit.
Denis