The Shelby Mustangs: Round 1
From the earliest days of the Mustang, Ford worked with Carroll Shelby to develop a high-performance version, shipping new Mustangs to Shelby American for modification. The 1965-66 Shelby GT350 had a modified 289 rated at 306 hp, as well as improved suspension and brakes. There was a race-ready GT350R version and a special version for the Hertz rental car agency, the 1966 GT350H.
In 1967, as Ford began to exert more control over the engineering of the Shelby cars, the GT500 was introduced, powered by a 335-hp 427-cid (7.0-liter) V-8 fitted with twin four-barrel carburetors. For 1968, the GT350 switched to a 250-hp, 302 (4.9-liter) V-8, while the GT500 KR (“King of the Road”) used the 428 Cobra Jet.
By 1969, Ford was making most of the design and engineering decisions. The GT350 switched to a 290-hp, 351-cid (5.8-liter) engine. Carroll Shelby terminated his relationship with Ford, and leftover 1969s were sold as 1970 models. Ford did modify a small number of 1971 Mustangs, called Shelby Europas, for a Belgian dealer, but the Shelby-Mustang association would go dormant for nearly four decades.
The Shelby Mustangs: Round 2
The re-association of Shelby and the Mustang started with the 2006 Shelby GT-H, a 325-hp version designed expressly for Hertz Rent-A-Car. The real deal came in the form of the 2007 Shelby GT500, which had a 5.4-liter V-8 supercharged for a staggering 500 hp. Ford also offered the Shelby GT, a civilian version of the GT-H available with a manual transmission.
Ford updated the Mustang in 2010, and the 2010 Shelby GT500 gained an additional 40 horsepower. Knowing a track-ready Camaro was on the way, Ford switched to an aluminum engine block for the 2011 GT500, taking 102 pounds off the nose to improve handling. The company also introduced the Shelby GTS, a package of appearance and braking add-ons for V-6 and V-8 cars. For 2013, the GT500 went haywire on horsepower with 663, enough to give it a claimed top speed of 200 mph.
The new 2015 Mustang brought about a new round of Shelby cars. The factory-built GT350 now had a 526-hp, naturally aspirated 5.2-liter V-8, and a race-ready GT350R variant. The 350 received updates and enhancements for 2019. In 2020, Ford launched the most powerful factory Mustang yet, the new GT500, with a supercharged 5.2-liter V-8 that turned out an unbelievable 760 hp. The car won several accolades, including a spot on the 2020 Automobile All-Stars list.