The Limited Edition 600 was a promotional unit developed by the Philadelphia sales district in May-June of 1969. The 600 consisted of special order, custom colored Mustangs in either "Flower Power Red" or "Groovy Green." This promotion was only available on hardtops or sportsroofs. Only 503 of Limited Edition 600s were produced. The Limited Edition 600 promotion coincided with Ford's national "Mustang Stampede" sales promotion. All 600s will be identified by the absence of a color code and a DSO of 16 plus 2783 through 2788 number on the door data plate. Most but not all 600s were powered by six cylinder engines, largest available was the 351-2v.