If Semon "Bunkie" Knudsen hadn't left General Motors to join Ford Motor Company in 1968, chances are there never would have been a Boss 429 Mustang. Knudsen had risen through the ranks at GM, first as general manager of the wildly successful Pontiac Division, then as head of Chevrolet Division. Knudsen was a proponent of racing and high performance, and that philosophy had resulted in a long string of Pontiac and Chevrolet muscle cars.
His successful stewardship of these two GM divisions rewarded him with a promotion upward into the corporation's top management ranks and what seemed like the fast track to the position of General Motors president. Knudsen would ultimately lose that battle to Ed Cole, and he wasn't happy with the GM board's decision. Henry Ford II felt Knudsen was the perfect man to inject some of the GM product and marketing philosophy into Ford. Over internal opposition, Henry Ford II offered Knudsen the top job at Ford. Knudsen cut his lifelong ties with GM and moved across town to the Blue Oval.
One of Knudsen's first moves was to put more muscle in the Mustang lineup. Ford had owned the ponycar market for the first four years it was on the market, but by 1968, the Camaro and Firebird were mauling the Mustang on the street with bigger-displacement engines. And in the SCCA's fast-emerging Trans-Am racing series, the Camaro Z28 was sticking it big time to the Mustang. Knudsen understood that both the Trans-Am series and the Mustang's lack of street performance cred were undercutting the brand's sales and image.
Knudsen immediately ordered Ford engineering and design staffs to conjure up a Z28-style Mustang. "Ford had the Mustang," Knudsen told author Donald Farr some years later, "which was certainly a good-looking automobile. There was nothing wrong with it, but there was a tremendous amount of people out there who wanted a good-looking automobile with performance. If a car looks like it's going fast and it doesn't, people get turned off. I think if you have a performance car and it looks like a pretty sleek automobile, then you should give the sports-minded fellow--the car buff--the opportunity to buy a high-performance automobile."
The result of this new Ford philosophy was the Boss 302 Mustang. Styled by Larry Shinoda, the GM styling wunderkind who had followed Knudsen over to Ford from Chevrolet, the Boss 302 looked the part thanks to its special stripes, big spoilers, and a radical new 290hp 302ci engine, identical in specs to the Z28.
Because of the modifications needed, Ford chose to outsource the Boss 302's suspension changes to Kar Kraft in Brighton, Michigan. Ford had turned to Kar Kraft in the past for special builds; they had been responsible for the construction of the GT40s that went on to win LeMans. While working on the Boss 302's underpinnings, Kar Kraft was also tapped to build what would eventually be called the Boss 429 Mustang. Knudsen was a strong supporter of stock car racing, and felt it necessary that Ford return to NASCAR dominance. He had a new race engine, the "Semi-Hemi" Boss 429, and he needed to make it legal in a hurry.
Thus, the Boss 429 Mustang was produced for one reason, and one reason only: to homologate Ford's new engine for NASCAR competition. Ford was still struggling to compete with Chrysler's 426ci Hemi, and the new "Blue Crescent" Boss 429 had all the earmarks of taking the game right back to Dodge and Plymouth. Based on a beefed, high-strength version of the production 429ci cast-iron block, the Boss 429 had four-bolt mains, a forged steel crank, massive forged steel connecting rods, and forged aluminum pop-up pistons with 10.5:1 compression for street use.
What set the engine apart and made it such a competitor was the magic in its aluminum cylinder heads. The heads featured a "crescent" shaped, semi-hemi combustion chamber with huge canted valves (the Boss 429's 2.3-inch intakes were the largest ever used in a Ford production engine) and huge round ports that could nearly swallow a tennis ball. Another unique feature was the "dry-deck" method that replaced the use of traditional head gaskets. Instead, O-rings were installed to seal the cylinders and the water and oil passages. Riding on top was a 735-cfm Holley, parked on an aluminum high-riser intake manifold. For driveability, a hydraulic valvetrain was employed. In full street dress, with air cleaner and emission equipment in place and closed exhaust, the Boss 429's output was advertised at a ridiculously underrated 375 horsepower. In race form on the NASCAR track, the Boss 429 put out nearly double that amount of horsepower. It was a 200-mph-at-Daytona, full-tilt racing engine toned down for the street.
The Mustang would never compete in a NASCAR race, and while the production Torino would have seemed to be the logical choice for the Boss 429, Knudsen wanted to give the Mustang an extra pump on the performance meter. Interestingly enough, a well-tuned 335hp 428ci Super Cobra Jet Mustang could kick a stock Boss 429 to the curb. Magazine tests of the period revealed the 428SCJ would run nose to nose with the Boss 429. That wasn't because the Boss 429 wasn't able to kick ass, it only served to show how undertuned the engine really was.
Each Boss 429 Mustang began as a partially completed Mach 1 Sportsroof that was delivered to Kar Kraft. These cars were already equipped with heavy-duty suspensions. Kar Kraft would add a .62-inch rear stabilizer bar and the modifications to the brakes and suspension they had first engineered for the Boss 302. Kar Kraft had reworked the platform's basic suspension geometry, and between computer analysis and plenty of track time, stiffer springs and revalved Gabriel shocks were specified for use with the wide 15x7-inch wheels and sticky F60 tires (the front fender wheel openings had to be cut and rolled under to clear the fat Goodyear Polyglas 60-series rubber). The rear shock placements were staggered to handle the increased lateral loads induced by the better adhesion levels generated by the wider tires.
Unlike the Boss 302, the Boss...
Unlike the Boss 302, the Boss 429's flanks were devoid of stripes, graphics and other visual nonsense. It was all about performance.
Kar Kraft had their engineering hands full trying to drop the King Kong Boss 429 between the Mustang's narrow shock towers. To shoehorn the big "Shotgun" 429 into the Mustang's narrow engine compartment, Kar Kraft had to cut the shock towers and move them outwards two inches. That required a wider strut tower brace. The front suspension was moved forward 1 inch, and special spindles, relocated upper and lower control arm mounting points, stiffer springs, and a .94-inch front stabilizer bar were added to improve the car's steering and handling characteristics due to the additional mass of the heavier engine. A slimmer power brake booster was required to clear the engine's left-hand valve cover. The battery was moved to the trunk for clearance and to improve weight distribution.
The remainder of the Boss 429 package consisted of Ford's Top Loader close-ratio, four-speed gearbox spinning a 3.91:1 rear axle with a Traction-Lok differential. The front shovel spoiler had to be shortened to clear the pavement since the Boss 429 sat 1 inch lower than stock height.
On the hood was a large scoop designed by Shinoda, driver controlled to allow cold air to the carburetor. Also included in the Boss 429 package were color-keyed, dual outside racing-style mirrors, engine oil cooler, and chromed 15x7 Magnum 500 wheels with those jumbo F60 Goodyears. The interior received he Mustang's Black Deluxe Dcor group, as well as a standard AM radio. An 8,000-rpm tach was included in the instrument package.
You're looking at the real...
You're looking at the real deal: a genuine 429-cube NASCAR engine, detuned to 375 horsepower at 5,250 rpm and 450 lb-ft of twist at 3,400 rpm. That was good for high 13s at over 100 mph.
Aside from an unassuming Boss 429 decal on the fenders, the car's discreet image belied the powerhouse that lurked beneath the hood. There were no stripes or other radical graphics, or blacked-out trim. Exterior colors were limited to five hues: Wimbledon White, Royal Maroon, Raven Black, Black Jade, and Candy Apple Red.
Assembly of the Job One 1969 Boss 429 Mustang was completed on January 15, 1969 at Kar Kraft's Brighton facility. Kar Kraft affixed a production sticker on the driver's door of each Boss 429, just above the warranty data plate. The first Boss 429 received number "KK NASCAR 1201." Because of the less-than-expected street performance of the early Boss 429s (one magazine called it a "stone"), Ford bowed to critics by making some revisions to the engine's internals by changing the bulletproof NASCAR rods for lighter units. This was done after job number 279. Not long after that revision, the magnesium valve covers were replaced with aluminum, and the valvetrain switched from hydraulic to mechanical.
Even these changes couldn't bring out the incredible top-end racing power of the Boss 429. The 735-cfm Holley carburetor didn't flow enough air, the camshaft was ground for low-end torque, and the factory-installed rev limiter all combined to prevent most adolescent speed jockeys from losing control and wrapping their FoMoCo-financed Boss 429 around a light pole.
The only transmission offered...
The only transmission offered with the Boss 429 was Ford's four-speed Top Loader close-ratio manual gearbox, mated to a 3.91:1 Traction-Lok rear.
When production ended in July, the last 1969 Boss 429 Mustang was numbered KK NASCAR 2059. Each engine block had the serial number stamped into the rear of the block as well as the transmission housing, the chassis, and the inner front fenders. A total of 859 were assembled (including two Boss 429 Cougars), although NASCAR homologation rules required only 500 be built.
Because of all the modifications necessary to fit the Boss 429 into the Mustang, Ford lost money on each one built, even with the hefty $1,208.35 tariff added to the Mustang's window sticker just for the engine. Each of the mandatory options for the Boss 429 were also tacked onto the bottom line, running the price tag up to nearly $5,000. Other options like the Shinoda-designed Sports Slats backlight louvers and rear deck spoiler were available at buyer preference.
The financial hit Ford took on each Boss 429 was considered a successful investment in NASCAR exposure and victories. Knudsen had coined the phrase: "Win on Sunday and sell on Monday," and believed the image rub-off was worth every dollar. During the 1969 racing season, Ford dominated the NASCAR circuit with the new Boss 429, winning more than half of the 54 races that season. At one point during the summer of 1969, Ford won 11 straight races thanks to the Boss 429. And while the Boss 429 did show up on the dragstrip in limited numbers, it never captured a national NHRA win.
The Boss 429, like the Boss 302, would continue through the 1970 model year. There were a few minor changes made to the '70 Boss 429, and Kar Kraft produced 499 before the program was canceled in January 1970. Knudsen had been railroaded out of his position of president at Ford in September 1969, and his successor, Lee Iacocca, didn't subscribe to Knudsen's enthusiasm for racing. It was a short-lived period of GM-style "go-go" product development and marketing, and Knudsen and his magnificent Boss Mustangs soon faded into Ford's more conservative culture.
The battery was moved to the...
The battery was moved to the right side of the trunk both to provide additional room in the engine compartment and add extra weight in the rear to improve traction.
Thanks to hardcore loyalists like Gregg Montgomery of Dayton, Ohio, the Boss 429 still stands as one of the most desirable Mustangs ever built. Gregg has an affinity for Ford's NASCAR connection. Before buying this Candy Apple Red '69 Boss 429 Mustang, he owned a Torino Talladega, which was Ford's introduction to NASCAR high-bank aerodynamics.
Gregg located the Boss 429 in December 1994 in the Atlanta, Georgia, area and brought it home. An expert machinist, Gregg tore the engine apart for a total rebuild. He kept the engine stock, faithfully following factory specifications; however, he did bump the compression ratio up a few points.
With the help of Bob Perkins, John Gumbert, and Doug Monroe, Gregg completed detailing and perfecting the Boss 429's pristine, 32,000-mile appearance. Along with all the mandatory Boss 429 options, it's also equipped with high-back bucket seats, center console, power steering, and power brakes.
Gregg's Boss 429 is a certified show winner, snaring awards like Best of Show at the Ford Expo and at the Dayton Concours de Elegance. It could just be the best Boss 429 in the country, recalling a time when motorsports competition was essential in Detroit, and dropping racing engines into street cars was a commitment that Ford called "Total Performance."
The Boss 429 had an aggressive...
The Boss 429 had an aggressive stance thanks to a 1-inch lower suspension and wide F60x15 Goodyear Polyglas tires. The front spoiler was standard as part of the Boss 429 package.
The Boss 429's interior was...
The Boss 429's interior was plush by muscle car standards. The Deluxe Dcor Group was included with the Boss 429; however, the front buckets in Gregg Montgomery's Mustang have the optional high backs.
Talk about a sleeper. The...
Talk about a sleeper. The only clue the King Kong "Blue Crescent" was under the hood was this simple Boss 429 decal on the front fenders.
Gregg Montgomery purchased...
Gregg Montgomery purchased his 32,000-mile Candy Apple Red '69 Boss 429 in 1994, began the restoration in 1998, and completed the project in 2002.
Each Boss 429 came with this...
Each Boss 429 came with this serial number label affixed to the driver's door directly above the data plate. The 1969 serial numbers started at 1201 and ran consecutively to 2059.
How serious was Ford about...
How serious was Ford about promoting the Boss '9? This two-page ad from a 1969 issue of Popular Hot Rodding showed the depth of Ford's Total Performance commitment. It runs the gamut, from the 427 SOHC "cammer" in the Top Fuel dragster to the NASCAR involvement in the ad copy.