The Mach 1 had less power for 1971 but looked meaner, with standard chin spoiler and hood scoops, and optional two-tone hood paint.

The 1971 Ford Mustang Mach 1

The 1971 Ford Mustang Mach 1 was not what it was in 1970 guise. First, base price went up a sizable $200 to $3268, and that bought only a standard 302-cubic-inch V-8, not a 351. Worse, retuning for this year's stricter emissions standards robbed the 302 of 10 horses, leaving it at 210 horsepower on unchanged 9.0:1 compression.

Yes, 351s were still available for the Mach 1 and other versions of the 1971 Ford Mustang: a 240-horsepower two-barrel ($45) and a 275-horsepower four-barrel ($93). With vehicle weights up so much, the base 200-cubic-inch six was sensibly scratched, leaving the torquier 250, though it, too, lost 10 horses, dwindling to 145.

At the top end of Mach 1 performance was again Mustang's big-block V-8. That engine was now a 429 -- which raised a few eyebrows -- but it wasn't the exotic semi-hemi of 1969-70. While this new Cobra Jet mill did have the same cylinder dimensions as the semi-hemi, it was essentially a short-stroke version of the Thunderbird/Lincoln 460-cubic-inch V-8, with wedge-type combustion chambers and conventional construction.

The 429 began the model year in regular (CJ) and ram-air (CJ-R) versions. Both had four-barrel carburetors, hydraulic lifters, and a nominal 370 horsepower, though most observers thought the cold-air ducting put the CJ-R at 380-385 horsepower. A solid-lifter Super Cobra Jet (SCJ) arrived a few weeks later at 375 horsepower, again with or without ram-air.

All 429s could be ordered with 3.91 and 4.11:1 rear axles, but the SCJ required those ratios and the optional Drag Pack with locking differential. None of these brutes was inexpensive at $372-$493, which likely explains why initial orders were so weak -- and why Ford decided to drop all three by midseason. Most probably went into Mach 1s, though they were technically available for any '71 Mustang.

A rear spoiler and Magnum 500 wheels were also optional.

According to Mustang chief program engineer Howard Freers, the 429 with its canted-valve heads "was a much wider engine than the 428, and that's why the car got wider" -- ironic in view of the engine's short tenure. "It took a [wider track] to get those monsters in there." But engineers took advantage of that to optimize handling for all models, which was "a major problem objective," Freers recalled. "I think we [improved] it…on the base model as well as the big-engine jobs." A key decision was fitting staggered rear shocks with any 351 or 429 engine.

The chassis wizards also recalibrated the base suspension to suit the bigger, heavier '71 package, revamped front-end geometry, and redesigned the steering gear. Cars with the comp suspension got variable-ratio power steering, allegedly borrowed from GM. Its chief advantage was needing fewer turns lock-to-lock, appreciated on fast, twisty roads.

The 351-cubic-inch engine was an upgrade from the base 302; racing-style twist locks were standard equipment on all Mach 1s in 1971.

A 429 Mach 1 was among the 1971 Mustangs that Chuck Koch tested for a January 1971 Motor Trend review. It did 6.5 seconds 0-60 mph, 13.8 at 104 in the quarter mile, topped out at nearly 114 mph and averaged just 9-10 mpg on premium gas.

By comparison, Motor Trend's test 1971 Mustang 302 hardtop posted 9.9 seconds 0-60 mph and 17.5 seconds at 78 mph in the quarter-mile. Top speed was 86 mph with the standard 2.79:1 axle. Fuel economy was 15.2-17.1 mpg on regular fuel.

The Boss 351 made most of the Mach 1 package standard -- and then added some options of its own. The next page tells you what this model had under the hood.

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  • Mustang had it all for 1969 -- except buyers. Sales were lower still in 1970. In 1969-1970 Ford Mustang, you'll find out how a new president infused the brand with more performance.
  • With Lee Iacocca back in the saddle, Ford's ponycar revsited its roots. 1974-1978 Ford Mustang tells the story of the Mustang II with its smaller, lighter design and return to rationality.
  • The 1971 Ford Mustang Boss 351 was Ford's final high-performance Mustang of the classic muscle car era. Here's a profile, photos, and specifications.