I built a 6.5 hp longtail from the ebay plans. Has a 7x4 backwater prop, what they suggested for the 6.5hp engine. Top speed i can get on my 1416 flatbottom (not a heavy boat), with just me and a battery in it, is 6mph. I was thinking about going up a size on props, as the motor does not even grunt turning the 7x4 (i did a couple of mods to the engine, but nothing major). Figured it would run a little faster than 6mph... What kinds of speeds are other people getting with similar setups and what should I expect?
