History of the Boss 302 and Boss 429 Mustang

 by Chris Repko

In 1967 the first big-block Mustang was introduced, the S-code 390 which was rated at 320 hp. This Mustang was not able to compete with the hot new SS 396 Camaro , so in 1968 the 428 Cobra Jet engine was introduced, giving the Mustang true muscle car status, but then why stop there? In February 1968 when Bunkie Knudsen arrived in Dearborn he brought with him some strong ideas concerning the Mustang. He believed the popular pony car was a good looking automobile, but that there were a tremendous amount of people out there that wanted a good looking automobile that could perform. He also knew that the Z/28 Camaro, created with SCCA Trans-Am road racing in mind, could handle and stop as well as it could accelerate. Big block pony cars were faster, but left something to be desired going through the curves with all that weight up front.

'70 Boss 429 Mustang

'70 Boss 429 Mustang

Bunkie was able to lure several GM Design Engineers over to Ford in 1968. One of them was designer Larry Shinoda, the man who had drawn up the Z/28's sport image in 1967. Shinoda was tasked with besting a performance legend that he had helped to create. Shinoda contributed the new cars stripes, spoilers and window slats, as well as its name. Two Boss Mustangs were born in 1969, both originally developed concurrently by Ford's performance contractor, Kar Kraft Engineering, in Brighton, Michigan.

The Boss 429 was also built in response to Chrysler's 426 Hemi and it's success in Nascar. Ford built a 427 Hemi-headed single overhead cam motor first, but it wasn't considered stock enough for the series so along came the "semi-Hemi" head 429. Kar Kraft was given the task of wedging a 429 into the Mustang. Quarter-mile times were reported to be in the lower 14s. Although another of the hot rod magazines, Car Craft, slightly modified the stock 429 and got a 1/4 mile in the mid 12s. The street cars came from the factory with a conservative cam and a somewhat small carburetor.

Starting with the 1969 model year the Ford brought the road racing Mustang program in house by creating the Boss 302 with styling by Larry Shinoda, suspension was design by Kar Kraft. Engineer Matt Donner was the man responsible for the excellent Boss 302 chassis, which quickly impressed the critics with the way it hugged the road. The engine was a Ford 5.0L block with the new 351 Cleveland heads. The car was originally to be called the Trans Am, until Ford found out GM had already licensed the name from the SCCA.

The Boss 302 was rated at 290 HP because insurance companies were beginning to penalize the muscle cars by tacking on higher charges to any car rated over 300 HP. Actual horsepower was closer to 350. (These are Gross HP figures, not Net, as used today). Race versions made 450 HP at over 8,000 RPMs.

Boss 302s also ran in Nascar's Grand American (GA) series. The car came with a wide-ratio or close-ratio 4-speed top loader. A 3.50:1 rear gear was standard with 3.91 and 4.30 optional. Front discs, rear drum brakes and 15-inch wheels were standard. Road tests at the time put 1/4-mile performance in the upper 14-second range. However, Super Stock magazine tweaked a '70 Boss 302 and put slicks on to get a time in the mid-13s.

How did the Boss 302 compare to the Chevy Z28? Well it seems that is was very close indeed. Chevrolet's Trans-Am Camaro took home the SCCA racing championship in 1969, while Ford's Boss 302 put the Mustang back on top in 1970. As for street performance, both machines relied on specially built 290 horsepower 302 cubic inch small block V8's. Performance was so close as to be a toss-up in most street or track encounters.

In late 1970 Ford stopped all factory-sponsored racing. So regrettably the fun had to end ... for now.

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Article Source: http://EzineArticles.com/?expert=Chris_Repko Jan. 8, 2006

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