I have a 40HP 2 stroke twin, tiller with power trim and tilt on a SeaNymph BT-175. The Vortex gave me a 150 RPM increase, and about 1 to 2 MPH increase in top end. The hole shot, with only me aboard, was much better with this prop as compared to the factory prop. Some of this may be due to being new, but I believe the upgrade to the Vortex made a difference. Deep Blue had the prop to me in 4 days and their price was the lowest I could find.