Ford's latest stallion packs an impressive 460-horsepower kick. Road Test Editor Howard Walker takes it for a ride. Come on, sing it after me: "Mustang Sally, think you better slow your Mustang down". Easier said than done. These days it's kinda tough to slow down Ford's latest Mustang GT 5.0. Not with a new, uprated 460-horse 5.0-liter V8 under its mile-long hood. Right now, sales of most fun-to-drive coupes are flatter than a Kansas parking lot. But the Mustang bucks the trend and continu...