I would suggest if you want any speed out of it to replace that straight shaft with a curved one which would be subsurface or even better yet a surface drive.Straight shafts angled down at mostly on scale boats or real one with a lot of horsepower,like a flat bottom drag boat.I see at the V in the bottom there's something there.Would be the perfect place for the shaft to come out. Another thing is to go with an already made prop like a Prather 270 or 275,a good starter prop for a Homelite/John Deere.