History of Ford Mustang : Fourth Generation (1971-1973)

Flat-featured and flabby, the 1971 Mustang was hardly beloved upon its introduction and has never really gained a place in enthusiasts' hearts. The wheelbase stretched to 109 inches and the car grew all the way to 187.5 inches long overall, and that was enough to kill the light, airy look and feel that had made the Mustang so engaging.

Still running on the Falcon-derived chassis, the '71 Mustang had engines ranging from the 250-cubic-inch six rated at 145 horsepower, through a plebeian 302 making 210 horsepower, two 351s at 240 and 285 horsepower and new Cobra Jet and Super Cobra Jet 429s pounding out 370 and 375 horsepower, respectively. Gone from the scene were both the Boss 302 and Boss 429 and in their place was a new Boss 351 with a (you guessed it) 351 V8 aboard that whacked out 330 horsepower.

Whether it was due to this new car's so-so appearance or the age of the Mustang concept is not known, but only 149,678 '71 Mustangs were produced. That's 41,049 less units than '70 and less than a quarter of the number sold during the 1966 model year.

While the 1972 Mustang was mostly carryover from '71, a change to net horsepower ratings and lower compression ratios (to reduce emissions) knocked the ratings of the 250-cube six to 98 horsepower, the lackluster 302 to 140 horsepower, and the three 351s offered to 163, 248 and 266 horsepower. Gone were both 429s, as well as the Boss 351. Sales slumped to just 111,015.

Power ratings dropped even further during the 1973 model year as emissions regulations began strangling output. The six now made a totally inadequate 88 horsepower, the 302 just 135 ponies, and the two remaining 351s (a two-barrel of Windsor design and a two-barrel Cleveland) just over 150 horsepower each.

Even though 1973 sales picked up to 134,867 cars, it was obviously time for Ford to rethink the Mustang.