The previous owner of my Nissan 5hp 2stroke swapped out the prop for a high thrust, it made a huge difference.
I use it on my 135 pound 9'6" rib and it can plane me along at 17mph. Most 'experts' will tell you it takes a 8hp to do that. It also planes my heavy 10'6" wooden bottom Achilles dinghy.
Here's a link that shows what's available for you from just one vendor, it pays to shop around.
Solas High Thrust Propeller » RubexProps
The down side of a high thrust is prop walk and higher boat speed at idle (and RPM will have to be adjusted upward because the load on the engine is greater).