The Mustang GT was back in 1983 as the sport upgrade package.
The most exciting part about this packages was that Ford had introduced a high-performance 5-liter (302 cid) HO engine package. The 302 V8 was taken out of the Mustang lineup after 1979 and replaced by a smaller, weak-kneed 255 cid V-8 sold only with automatic transmissions and cruising gear ratios. A woefully inadequate turbocharged 4-cylinder combination was marketed but ultimately scrapped. The Mustang was losing image after 15 years on the market, in spite of a new body and a superior TRX handling package. The 302 arrived just in time. It was good for 157hp and was marketed as the 5.0L V8 engine. That was 1982 and for 1983 things improved even further.
The GT also received the addition of a 600-cfm four-barrel Holley carburetor and a host of other changes to the V8. The end result was that the 5.0L was now good for 175 horsepower. The GT could sprint from 0-60 mph in less than 7 seconds, a huge improvement.
Other GT changes for 1983 included a wide black hood stripe and deeper fog lights in the new, less angular spoiler. It also got the rear facing non-functional hood scoop and 16 spoke alloy wheels (many chose the optional 3 or 6 spoke cast aluminum TRX wheels). GT standard upgrade equipment included the 1983 standard new black grille, body-colored headlamp trim, aerodynamic front skirts, rear spoiler, and performance suspension and handling.
There were some suspension modifications to the 1983 Mustangs, but the most noticeable was the tire changes. GT with the 205/70HTx14 wheels and the lower profile P220/55R 390 TRX Michelin tire really looked and performed better.
Later in the year a $250 higher Turbo GT was offered with a 2.3L, electronic fuel injected Turbo 4-cycle engine. It was known as the Turbo GT and is considered a separate variant.