While most of the Mustang was carried over in late 1982 for 1983, there were some changes and improvements on the then five-year-old "Fox-platform" model. The front fascia was restyled with a more rounded nose and reshaped grille. New, wider horizontal taillights with dedicated amber turn signals replaced the vertical sectioned units. This was also the first Mustang to use the "Blue Oval" Ford emblem on the exterior, both front and rear. Ford added a
convertible to the Mustang line for 1983, after a nine-year absence. The majority of the convertibles were equipped with the new
Essex which replaced the
I6 engine. The small block V8 engine received a four-barrel carburetor and a new intake manifold, bringing power to . The 2.3 L four-cylinder Turbo also returned mid-year 1983, now fuel-injected, and producing . Sales of the Turbo GT were hurt by a higher base price and lower performance than the . For 1984, the GL and GLX were dropped, leaving the L, GT, and Turbo GT while adding new additions, the LX and
SVO. Ford also recognized the 20th anniversary of the Mustang with the G.T.350, essentially a limited run of GTs and Turbo GTs. A total of 5,261 G.T.350 hatchback and convertible models were built, all trimmed with Oxford White exteriors and Canyon Red interiors. They featured red G.T.350 rocker stripes and tri-bar Pony emblems on the front fenders. Two V8 engines were available, a carbureted version (with manual transmission only), or a new electronically fuel-injected engine (with automatic transmission only). A new "Quadra-Shock" rear suspension, which replaced the slapper bars with horizontally mounted axle shocks, became available after a few months of production. After 1984, the TRX option was retired for the Mustang. The new
Mustang SVO appeared first in 1984 and was produced through 1986. The 2.3 L turbocharged inline-four produced initially for 1984, uprated to beginning halfway through the 1985 model year, and ending with for 1986. Four-wheel disc brakes, 16-inch wheels, and an SVO-specific bi-plane rear spoiler were a few of the differences between the SVO and the rest of the Mustang line. The unique front fascia featured an offset hood intake duct for the turbo intercooler and a grille-less nose with sunken single rectangular sealed beam headlamps, flush inboard parking lamps, and wraparound outer turn-signal lamps. The front end was intended to use flush aerodynamic composite headlamps with replaceable bulbs, but the US DOT had not approved these in time for production. Aero headlamps finally appeared on the 1985½ SVO.
Hagerty (Insurance), specializing in classic cars, calls the introduction of the first Mustang in 1985 the end of the
Malaise era in American auto design. For 1985, the front fascia was restyled with a grille-less nose with a horizontal air intake slot. The Mustang GT received new E5AE cylinder heads, a revised Holley four-barrel carburetor, a new and more aggressive roller camshaft (only in models with the manual transmission), less restrictive exhaust manifolds, and a pseudo-dual exhaust which brought more power to a conservatively rated engine. This would be the last carbureted V8 in the Mustang. The 1985 model year dropped the L and Turbo GT, leaving the LX, GT, and SVO models. For 1986, Ford released the first multiport fuel-injected V8, rated at . In 1986, the Mustang GT saw drivetrain upgrades including a new 10.5-inch (upgraded from 10") clutch. A 7.5-inch rear-end continued in 2.3, 2.3 turbo, and 3.8 L applications, but models included a new 8.8-inch unit. Central fuel injection was used on the non-turbo 2.3 L in automatic versions, but was dropped the following year and replaced with a more efficient multi-port fuel injection. The rear center high-mounted brake light was now mounted on the now-standard rear spoiler for hatchbacks, inside the bottom of the rear window of the coupe, and on the rear edge of the standard luggage rack on convertibles.
Engines Engines for the 1983–1986 models included the 2.3 L, the 2.3 L turbo — now fuel-injected and available only in the Turbo GT and SVO, the 3.8 L
Essex V6, and the High Output (H.O.) V8 engine, with a new four-barrel carburetor made by
Holley. The 3.3 L
straight-six engine was dropped after the 1982 model year.
Transmissions Transmission availability varied behind the H.O. each year. The Tremec four-speed manual overdrive (SROD) carried over from the 1982 model year and was the standard transmission behind the 302 in 1983. Shortly after the 1983 model year started, the "standard duty"
Borg Warner five-speed manual overdrive transmission (T-5) became available and it was then the standard transmission behind the 302 engine, with the SROD becoming optional — with an invoice credit — for the remainder of the model year. For the 1984 model year, the
four-speed automatic overdrive (AOD) transmission became available for the first time in the Mustang model line, and it was available behind the 302 engine only with throttle-body electronic fuel injection (called 'Central Fuel Injection' or CFI). The T-5 was still available with the 4V carb induction system. For the 1985 model year, the Borg-Warner T-5 transmission was upgraded by Borg-Warner to "Heavy Duty" status, also known as "World Class". The WC T-5 was still only available with the 4V induction system. The AOD transmission was also still only available with CFI induction carried over from 1984 but shortly after the model year started it received the exhaust system from the 4V/T-5 engine, and a 15 hp increase. In 1986 the H.O. engine was now sequentially fuel-injected (SEFI), and was available with either automatic or manual transmissions.
Motorsport The Mustang became Ford's main challenger in the early years of
Group A touring car racing in Europe and
Australia. However, the V8 engine was not a contender in the various European championships and was replaced in 1985 by the turbocharged
Ford Sierra XR4Ti. Australian
Dick Johnson Racing purchased two Mustangs built by
Zakspeed in mid-1984 for use through
1985 and
1986 Australian Touring Car seasons as
Ford Australia did not homologate either the Australian built
Ford XE Falcon or its replacement, the
XF Falcon, for racing. Johnson had a race win in the Group A support race for the
1985 Australian Grand Prix, as well as several placings in the
1985 and
1986 Australian Touring Car Championships. The Mustang's competitive life in Group A came to an end at the end of 1986 and was replaced in 1987 by the European-designed turbocharged
Ford Sierra RS Cosworth. ==Mexico==