In 1968 Ford decided to give the Shelby Mustang a new look and a distinctive feel to help set them apart from existing vehicles. The 1968 Red Shelby Mustang was created with a heavier build than the previous models and Mustangs in general. The new model of Shelby was created wider grills and a unique convertible top. Now the 1968 Red Shelby Mustang had a roll over convertible top that was designed to enhance safety. In addition to consumer safety the 1968 Red Shelby Mustang was also designed with environmental safety in mind. In order to stay within acceptable emission limits the new Shelby used the new 302 V-8 engine.By the middle of 1969 Ford decided to make an additional option available for the 1968 Red Shelby Mustang. After deciding to make the Cobra Jet engine available for the Mustang Ford decided that they should also make the option available for the Shelby. The original 428 block that was developed and placed into the Cobra GT500 was supplanted by the Cobra Jet engine unit. The Cobra Jet engine boasted a low riser, completely revised 427 cylinder heads that had large ports that were rectangular in shape. The Cobra Jet unit also had a special intake manifold that was designed with a duel plane and it also had a large, four barreled, Holley carburetor. With this option installed the 1968 Red Shelby Mustang was referred to as the Cobra GT-500KR and was nick named the 'King of the Road'
With the special addition the 1968 Red Shelby Mustang was advertised as having a 335 hp @ 5600 rpm rating to satisfy certain insurance issues and concerns. In reality the 1968 Red Shelby Mustang with the Cobra Jet engine really had nearly 400 hp @ 5600 rpm. The huge car was able to reach truly astonishing speeds that easily exceeded 210 kph. While this was enough to leave any racing enthusiast breathless there was more to come.The new engine made it possible for the 1968 Red Shelby Mustang to go from 0 miles per hour to 100 miles per hour in just fourteen seconds. Most modern cars can only reach a fraction of that speed in that time frame and cars pre dating the 1968 Red Shelby Mustang took at least 17 seconds to perform the same feet. For many the 1968 Red Shelby Mustang was a race car that could be driven on the highway.While the prices of many competing cars were being raised because of inflation the 1968 Red Shelby Mustang did not experience a large price change. Since the price of the 1968 Red Shelby Mustang was remaining stable the sales volume increased but eventually bottomed out. As those who wanted the new Mustang purchased them sales eventual slowed then stopped. The 1968 Red Shelby Mustang was different than its predecessors. Instead of being a car designed for racing enthusiast the newer Shelby's were being designed with average consumers in mind. Ford was concentrating on developing cars that were comfortable to driving and suited to casual road trips.