The Mercury 310 Sport 2007 vs Mercury V-400 2008 comparison sits squarely in the category of decisions where specs alone won't tell the whole story — intended use, storage, and long-term ownership costs all factor in.
Size is the most obvious dividing line here. The Mercury V-400 2008 measures 13,0 feet overall (2008), giving it roughly 12,0 additional feet of deck space compared to the Mercury 310 Sport 2007 at 1,0 feet (2007). Weight tells a clearer story for trailering families: the Mercury V-400 2008 tips the scales at 313 lbs — 199 lbs less than the Mercury 310 Sport 2007 at 114 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.
The power gap is worth calling out. Rated to 40 hp, the Mercury V-400 2008 has a 25-hp advantage over the Mercury 310 Sport 2007's 15-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Mercury V-400 2008 is rated for 6 passengers, while the Mercury 310 Sport 2007 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Mercury V-400 2008 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Mercury 310 Sport 2007 comes in at 8 lbs per hp versus 8 lbs per hp for the Mercury V-400 2008. The lower the ratio the more explosive the acceleration — meaningful on a short RIB where bursts of speed, quick planing, and agility in surf or tight waterways define the experience.
Bottom line: Choose the Mercury V-400 2008 if your priority is putting more people on the water — it handles 6 passengers and at 13,0 ft it has the deck room to back that rating up comfortably. The Mercury 310 Sport 2007 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.