What comes under the hood of a front-wheel-drive 2007 Pontiac G6 Convertible is entirely dependent on the exterior badge. If there are only two letters, GT, momentum comes from a 12-valve, 3.5-liter V6 featuring a cast iron block and aluminum heads; this base engine is rated at 201 horsepower at 5,800 rpm and 221 lb.-ft. of torque at 3,800 rpm while running on regular gas. A four-speed automatic with a manual-shift mode is the only transmission available. The EPA suggests that drivers will realize 19 mpg city and 27 mpg highway with this setup.