Since the Ford Motor Company released the Mustang in 1964, the auto manufacturer has debuted many impressive iterations of their groundbreaking pony car. In 1969 and 1970, Ford offered three stunning versions of the Mustang that outperformed previous iterations — the Boss 302, Boss 429, and Boss 351.
Ford released these vehicles at an important time when the pony car competition was starting to heat up against General Motors. Here’s what you need to know about these bold and stylish 1970 Boss Mustangs.
History of the Boss Mustang
Ford had a great deal of success with the first generations of the Mustang. By 1969 — five years after the Mustang’s debut — the company had already sold around two million units. Although the traditional Mustangs featured much to write home about, the kings of the road in the late 1960s were the Shelby GT350 Mustangs. The 1965 and 1966 Shelby models were equipped with powerful 289 cu in (4.7) Windsor K-Code V8s with 4-barrel carburetors.
In 1967, Ford introduced a new Mustang body that was larger and heavier. One of the primary reasons for this shift was due to General Motors’ impressive Chevrolet Camaro. Ford finally had some competition in the pony car market, and the manufacturer responded by redesigning the Mustang body to accommodate big block engines.
Before the introduction of the Camaro, Ford was perfectly content to leave the most powerful Mustangs to Shelby, and the company had even increased the volume of the Shelby Mustangs by moving production from Los Angeles to Ionia, Michigan.
When the Z28 Camaro came on the scene, Ford knew that it needed to improve upon the non-Shelby Mustangs. The Z28 was a special street version of Chevrolet’s Trans Am racing vehicle, and the vehicle could outperform the small block Mustangs.
Ford began focusing its attention on Trans Am racing to compete with the Camaro. Chevrolet’s Z28 Camaro beat out the Ford Mustang and went on an impressive winning streak from late 1967 to 1968. The Camaro won the manufacturer’s title in 1968, leading Ford to introduce major changes to compete with General Motors both on and off the racetrack.
Boss Ford Mustang 1970 Models
The Ford Boss program came on the scene in late August 1968, and the program presented the 302 and 429 prototypes to Ford management only three weeks later. At the time, the Boss 302 was known as the “SR-2,” an abbreviation for “Sedan Racing, Group 2.”
Larry Shinoda suggested to the President of the Ford Motor Company, Bunkie Knudsen, to change the name to “Boss” because “SR-2” seemed to follow the same letter and number structure as the Z28 Camaro. Knudsen immediately took to the name, and the Boss 302 and 429 Mustangs were born. Then, in late 1970, the company introduced the Boss 351.
1970 Mustang Boss 302
Ford created the 302 CID (5.0 L) Boss 302 OHV V8 in 1968 for Trans Am racing, but the engine was also available for the street version of the vehicle. The engine featured four-bolt main bearings on its center three caps, 780 CFM 4-barrel Holley carburetor, dual-point distributor, high-pressure oil pump, high-rise aluminum intake manifold, screw-in freeze plugs, pushrod guide plates, screw-in rocker arm studs, and more. The engine boasted an impressive 290 horsepower and could go from 0 to 60 mph in just under 7 seconds.
In addition to its impressive engine, the Boss 302 package came with an eye-catching style, including inverted “C” stripes, a black-out grille, black headlamp sockets, a black tail light board, a black rear decklid, and a black front spoiler. The package also came with power steering and a rear-wing adjustable spoiler.
1970 Mustang Boss 429
The Boss 429 boasted an unforgettable 429 cu in (7.0 L) Ford 385-series V8. This engine featured aluminum cylinder heads, four-bolt main caps, a forged steel crank, forged connecting rods, and a 735 CFM 4-barrel Holley carburetor. The vehicle had 375 bhp at 5200 rpm and 450 foot-pounds of torque at 3400 rpm.
The main reason why Ford equipped the Mustang with this engine was to homologate it into NASCAR stock racing. For the engine to be eligible, Ford had to install it into at least 500 vehicles. Rather than choosing a car that was larger and perhaps more suitable for the Boss 429 engine, Ford executives decided to install it into the Mustang. To fit the engine into the model, Ford had to make significant modifications to the Mustang’s suspension.
1970 Boss 351 Mustang
The Boss 351 served as the successor to the Boss 302, but unlike the 302 and 429, the model wasn’t used for racing homologation. By the time Ford got to work on the 351, the company had halted its racing program due to the economic recession. The plan for the vehicle was already in place before the program stopped, so Ford went ahead and created this stunning vehicle. The Boss series had already become a great success, so the 351 served as a marketable continuation of the series.
The vehicle also differed greatly from the 302 and 429 because it was based on the Mustang Sports Roof model. It featured a high output 351 cu in Cleveland 4-barrel V8 engine with 4-bolt main bearing caps, solid lifters, a mechanical cam, and a high-rise aluminum intake manifold. Additionally, it featured the 750 CFM Ford 4-barrel carburetor and boasted 330 hp at 5400 rpm.
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