The 1990 Mustang GT looked and felt the same as the 1989 Mustang because it was basically unchanged bar some small things. That wasn’t a bad thing per se, because Ford really nailed the Mustang with the 1987 upgrades and saw no reason to change things given the strong response from consumers and motoring press alike. There were some upgrades, but it was minor stuff.
Performance upgrades included stainless steel exhaust and headers, 10.84 inch front brakes, progressive springs, 1.3 inch front anti-sway bar, 0.83 inch rear anti-sway bar, performance struts and shocks, and 15 x 7 inch wheels with performance P225/60VR-15 Goodyear tires.
The front of the 1990 Mustang GT had the lower air-dam front valance and a grille-less nose clip and integrated round fog lamps. Air was ingested into the engine compartment through that wide intake located between the fog lights. Headlights were covered and there were small scoops on the front of each wheel well that also looked more aggressive and sporty. The 1990 Mustang GT came standard with 16 spoke sport wheels, color matched body-side moldings, solid front grille.
Engine wise, the 5.0L stayed steady at 225 horsepower. Ford’s changes in 1987, including the following all stuck: electronic engine control module (EEC) and a change from a speed density system, which compared manifold pressure, vacuum and barometric pressure to the simpler and very accurate mass airflow system which calculated the airflow entering the engine as it passed over a heated wire. Ford also got rid of the emissions friendly high swirl heads for higher compression and better performing heads, increased the throttle body size for better breathing and reworked the exhaust system. The 5.0 liter engine saw low-end torque improve with these changes.