The Nitro 640 2007 vs Nitro Z-6 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.
On paper these two are close siblings in the size department — Nitro 640 2007 at 16,0 ft versus Nitro Z-6 2008 at 17,0 ft. Weight tells a clearer story for trailering families: the Nitro 640 2007 tips the scales at 1 092 lbs — 957 lbs more than the Nitro Z-6 2008 at 135 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 130 hp, the Nitro Z-6 2008 has a 40-hp advantage over the Nitro 640 2007's 90-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Nitro Z-6 2008 carries 31 gallons versus 24 gallons in the Nitro 640 2007. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
Both boats are rated for 4 passengers — a good fit for a family of four or five plus guests. Comfort at capacity is another matter; the longer hull typically means more seat options and better weight distribution.
At this size, power-to-weight ratio matters more than outright horsepower. The Nitro Z-6 2008 comes in at 1 lbs per hp versus 12 lbs per hp for the Nitro 640 2007. 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.
The Nitro Z-6 2008 has a documented top speed of 43 mph. Speed data wasn't available for the other model.
Bottom line: Performance buyers should lean toward the Nitro Z-6 2008 and its 130-hp ceiling. If fuel economy and quieter running matter more than top-end speed, the Nitro 640 2007 with its 90-hp rating is the more economical daily driver.