MVVS .40 Prop
Flatspins, I ned a little more information. Is the MVVS .40 A Quickee 500 or a regular MVVS .40? If the engine is a Q500, you can try an APC 9X7 or a 9X8, I prefer the 9X7. Also, APC makes a special pylon prop, 8.75X7.50, which also is very good.
If the engine is a regular .40 I always use an APC 11X4.