While everyone else is downsizing and adding turbos, the new SRT Viper marches on with an 8.4 liter V-10 engine. Not only does this motor produce 640hp, but the engine also weighs 25lbs. less than the outgoing engine. All that power with less weight is a vicious package of brains and brawn. It may not have all the new tech that modern supercars boast, but no one can debate what is arguably the engine equivalent of a double-barreled shotgun.