RE: New speed plane
umm.....
Holy C____ppppppppppppp
With that setup, you will want to run smaller diameter/higher pitch props. Keep the P factor to a minimum and the frontal area down.
You may want to start with the 8.8x9.5 apc racing props, and clip them down to 8" dia.
(I showed the photo to Dub, he said the same thing about the props - smallest diameter you can find/make)