2008 Nissan 350Z Roadster. The 350Z Roadster is powered by a 3.5-liter V6 engine that makes 306 horsepower at 6,800 rpm & 268 pound-feet of torque at 4,800 rpm. Edmunds writes: “The V6 is quite docile, though, & opening it up a bit produces an enjoyable and throaty growl.