With the introduction of the Falcon-based
Mustang Ford wanted to show that the car really was
a sports car by racing. Unfortunately, Ford had gotten
out of all factory-backed racing in 1957. After Lee
Iacocca became Ford General Manager in 1960 he met
Carroll Shelby for the first time. Shelby was building
a sports car in California and got agreement to use
Ford's small block V8 for the project. Again in 1964
Ford came to Shelby to help "hot rod" the
The idea was to compete in SCCA road racing.
The GT350 was born and it dominated SCCA B/Production
winning the championship three years in a row. This
gave Ford the sporty image they were looking for. The
SCCA started a new series for American production-based
sedans called the Trans-American Sedan Championship.
Shelby was again called on to provide the racecar building
In 1968 production of the Shelby cars shifted from his California site to the Midwest and more under Ford's control. The '68 car used a slightly modified version of the 428 Police Interceptor motor, and even a few had 390's due to a lack of available 428's. These cars still lost the drag strip wars to the top-of-the-line 396 Camaros. Later in 1968 the Cobra Jet motor became available in the model called the GT500KR. Only 1,314 were made in '68 including 381 convertibles. 1969 was the last year for Shelby production, although some of the cars were unsold by year-end and were then sold as 1970 vehicles.
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 by specialty builder Kar Kraft,
and engine by Ford using the 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 290HP
because insurance companies were beginning to penalize
the muscle cars by tacking on higher charges to any
car rated over 300HP.
Actual horsepower was closer
to 350. Race versions made 450HP at over 8,000rpm.
Boss 302's 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 are 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-13's.
In late 1970 Ford stopped all factory-sponsored racing.
The Boss 351 engine used the Cleveland block with the heads from the Boss 302. It came with a 4-speed and a 3.91:1 rear axle and still with rear drum brakes. The engine was available in the newly redesigned '71 Mustang that weighed over 3800lbs, about 300 more than a Boss 302. Road tests at the time returned 1/4 mile ET's in the low 14's, although it was hard to get accurate times because Ford had shipped "specially modified" cars to the testers of most magazines that ran much quicker. This seemed to be a fairly common practice in the muscle car days when quarter-mile times related directly to sales.
The Boss 429 was built in response to Chrysler's 426 Hemi and its 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. The task of wedging a 429 into the Mustang was given to Kar Kraft. Quarter-mile times were reported to be in the lower 14's. Although another of the hot rod magazines, Car Craft, slightly modified the stock 429 and got a 1/4 mile in the mid 12's. The street cars came from the factory with a conservative cam and a somewhat small carburetor.
428 Cobra Jet
the big blocks hit the pony cars in '67 with the 390
Mustang and the 396 Camaro, Ford was caught on the
short end of the muscle car wars. The 396 was about
a second quicker in the quarter mile than the 390.
Shelby was the first to offer competition with the
428-powered GT500, but this was still a bit slower
than the Camaro. It was actually a Ford dealer and
drag racer named Bob Tasca who solved the problem by
bolting 427 heads on the 428.
These free-flowing heads
combined with the torquey 428 really made the car move.
Soon Ford had their own version, the 428 Cobra Jet.
This put 1/4-mile times at about 14 seconds. This engine
was first available in 1967 as a $420.00 option. About
2,800 units were sold in late '67, 13,000 in '69 and
2,700 in '70.
429 Cobra Jet
option was available only in 1971 with 370HP and a
1/4-mile time of about 14 seconds. Only 1,300 were
sold. This was the end of the muscle car era for the
Mustang as low compression engines came in to use for
the "bad old days" of the '70s.