I finally looked at top speed with my GPS on my '84 248 Sportsman with a '99 5.7L EFI 260 hp engine. With four adults (I'd guess 750 pounds), 3 kids (another 200 pounds), full tank of gas (just splashed it Friday), a days worth of food, drink, gear and one kayak - I measured 38 mph at 4300 RPMs. Can't tell you the size of my stainless prop. Not too bad for a 25-year old lady with probably 25 coats of bottom paint.