Wayne Cook
September 1, 2001
Photos By: Mustang & Fords Archives

A prominent player in the development of the Boss 302 Mustang styling was Larry Shinoda. Hired away in August 1968 from the GM camp where he achieved fame as the designer of the '63 Corvette Sting Ray, Shinoda was responsible for many of the significant design features found on the Boss 302. These features included the graphics as well as the spoilers and rear-window slats available optionally on the car. At the same time, Shinoda was also the one to remove other design ornamentation features found on the regular '69 Mustang such as the fake sidescoops and roof-pillar horse emblems.

For '69, the Boss 302 was available in only four colors: Bright Yellow, Acapulco Blue, Calypso Coral, and Wimbledon White. For '70, most Ford colors were available. In addition to the changes made in the regular Mustang, changes for the '70 model year to the Boss 302 were several. These included the addition of the rear antisway bar, cast-aluminum valve covers on the engine, and smaller intake valves.

Although the Ford Trans-Am effort for '69 ended in frustration, the '70 season saw Ford and the Boss 302 victorious, with the No. 15 car of Parnelli Jones ending up in the Winner's Circle.

The Boss 429 was developed concurrently with the Boss 302; however, its final production was done at Kar Kraft in Brighton, Michigan. The Boss 429 Mustang was designed and offered to the public in order to homologate the 429 engine for NASCAR racing. SportsRoof Mustangs originally produced to receive the 428 Cobra Jet engine were shipped to Kar Kraft for completion. To accept the larger engine, Kar Kraft lowered and moved outward the front suspension. Special spindles and control arms unique to the Boss 429 were used. Outwardly, these special Mustangs were identified by a Boss 429 fender decal. The Boss '9 also came equipped with dual racing mirrors, a front spoiler, a functional hoodscoop, and a trunk-mounted battery. An engine oil cooler, power steering, and front disc brakes were also included. The standard transmission was a close-ratio four-speed connected to a 3.91:1 Traction-Lok rear axle. Magnum 500 wheels sized 15x7 were standard and shod with F60-15 tires. It was a good-looking Mustang although less flamboyant than the Boss 302.

Under the hood, a beefed-up version of the 385-series 429 engine was used. The blocks featured four-bolt main caps and a forged-steel crank. Special-design aluminum heads were used and no head gaskets were employed on the engine. Instead, the cylinder bores were sealed by O-rings. The heads featured a modified hemispherical-shaped combustion chamber referred to by Ford as the "crescent design," and the Boss 429 engine became known as the Blue Crescent 429 in Ford circles.

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In '71, the Mustang was redesigned yet again. Now the car was larger and heavier than ever before. Even the wheelbase was lengthened to 109 inches, up 1 inch from previous incarnations.

Home-Brewed Boss
Those of you wanting to produce something different might be interested in concocting your own "homemade" version of the Boss 302. The durability of the Windsor block, combined with the flow capacity of the 351 Cleveland heads, either the two- or four-barrel version, can make an interesting and powerful combination. Keep in mind that, in 1969, the Cleveland heads were an advanced design for their time, which featured huge ports and valves. However, they were designed without the tremendous benefit of computer-aided testing. Hence, many of the newer cylinder heads made for the Windsor 302 will give you a more balanced power curve.