The 2020 Ford Mustang Shelby GT500 thunders into the muscle car ring with 760 hp

Despite so much talk of electric cars and autonomous driving, you can still buy a 797-horsepower Dodge Challenger or a 650-hp Chevrolet Camaro. But the rival Ford Mustang has stayed out of the horsepower wars — until now. Unleashed at the 2019 D…