Ford execs apparently didn’t have any big plans to make a big splash for the Mustang’s 20th birthday, but cranked out 350 1984 20th Anniversary G.T. 350s that carried a lot of options to make them unique — including the G.T 350 moniker made famous by Carroll Shelby in the late 1960s.
The trouble with the plan was that Shelby owned the rights to the G.T. 350 name. And no way he was going to waste that legacy on a turbo four with 145 hp
Ford didn't think they'd have to give way, and were wrong. They had screwed a lot of small people through the years (intermittent wipers for example) but hadn't tangled with a legend like Shelby before. Hell, they used him to teach Enzo a lesson, you'd think they would have realized he wasn't going to take any shit from them.
Carroll didn't use the GT 350 badge until 2011, when the car was finally competitive.
http://www.oldcarsweekly.com/car-of-the-week/car-of-the-week-1984-ford-mustang-g-t-350
https://www.thoughtco.com/1984-ford-mustang-anniversary-edition-gt350-2464614