Under the hood of the 2015 Dodge Viper SRT models is the all-aluminum, mid-front 8.4-liter V-10 engine that delivers 645 horsepower and 600 lb.-ft. of torque – the most torque of any naturally aspirated sports car engine in the world. The aluminum “X” brace ties the suspension pickup points to the magnesium cowl super casting and contributes to improved torsional rigidity and stiffness.