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It’s in the name. The self-proclaimed Ford Mustang Boss 429 demands reverence. The Boss 429 is ready to pounce on looks alone, with sharp, aggressive contours and a crouched stance. It’s a proper Mustang, prepared to break away from the crack of a starter’s pistol. Unfortunately, looks aren’t everything. When Ford released the Boss 429, it only sold 857 units compared to the Mustang Shelby GT500’s 1,872, making less horsepower and roughly the same price. Since that time, the Boss 429 has garnered utmost respect, but we’re not convinced. We’ll see if the Boss 429 deserves its accolades.

The Boss 429 engine had some teeth

Ford Mustang Boss 429 engine on display
Ford Mustang Boss 429 engine | National Motor Museum/Heritage Images/Getty Images

The Boss 429 used a bored 385 cubic-inch block, rated at 375 horsepower. It used aluminum cylinder heads with valves angled at 30-degrees that catered to hemispherical pistons. Instead of head gaskets, the Boss 429’s cylinder heads used metal rings that would crush between the head and block, sealing the combustion chambers. It even employed a separate rocker for each valve, according to Mac’s Motor City Garage

Ford made the Boss 429 engine to compete in NASCAR, and it was only thanks to homologation rules that a customer could walk into a Ford dealer and buy one. Although Ford fitted the Boss 429 with a 1,000 CFM bespoke Holley carburetor for competitions, it was stifled by a 735 CFM carburetor in its road-going version. Ford only made the Boss 429 engine in production cars for two years, making it one of the rarest Mustangs in existence.

Ford’s Mustang Boss 429 got a few extra goodies

1970 Ford Mustang Boss 429 parked outside
1970 Ford Mustang Boss 429 | National Motor Museum/Heritage Images/Getty Images)

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The 1969 Ford Mustang Boss 429 didn’t offer much beyond the engine. It received a close-ratio 4-speed transmission and a locking differential sporting a 3.9:1 axle ratio, thus giving it all the makings for rapid acceleration. Ford also gave the Boss 429 lowered suspension, big sway bars, and front disc brakes with extra stopping power.

How fast was the Ford Mustang Boss 429?

Although the Shelby GT500 was a hair faster, the Boss 429 managed to squeeze 60 mph out of 5.3 seconds and complete the quarter-mile in 12.3 seconds. While those numbers are impressive even by today’s standards, it’s nowhere near the fastest muscle car of the decade. That belongs to the Shelby Cobra 260, which completed the sprint to 60 mph in 4.5 seconds. The Boss 429 was supposed to be the car to beat the Mopars, and it handily won the 1969 NASCAR season. However, 1970 saw a resurgence in Mopar, and the Dodge Charger would go on to win the next three consecutive seasons.

Get a 1971 Ford Mustang Boss 351 instead

1971 Boss 351 Mustang parked outside
1971 Boss 351 Mustang | Getty Images

While the Ford Mustang Boss 429 is undoubtedly one of the most powerful cars from Ford, plenty fast and dominant in NASCAR, it doesn’t seem to have accomplished quite enough to deserve its praise. It is thus highly overrated, but maybe not the most overrated muscle car. If rarity is the only qualifier for a desirable Mustang, then consider the Boss 351. It was only a half-second slower than the Boss 429 despite using a small block, and was only made for one year in 1971. 


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