GTR,
I just sold my Prather spitfire 7.5. ****, it was fast. My advice, add a 1 to 1 1/2 inch spacer between the mount and the transom. Really makes a difference in spped and ride attitude. Three blade X-447 or 450 cut back and thined.
Sold it because as it stalled out in the lake the ass end with the engine being on the back was so heavy it would go under water only leaving the tips of the sponsons showing. Very hard to retrieve w/no retrieve boat! Not all of us have our personnal retrieve boat! LOL ;D