Ford Boss 429 V8
The Boss 429 V8 was a 2-year-only option available in production cars, but its huge impact on Ford’s performance still remains.
Ford Motor Company announced its latest racing engine to the public in the fall of ’68, it was almost named something else. imagine that.
The Boss 429 is based on Ford’s 385 engine series, it’s 6-year design process was so it could replace the two existing Ford large engine families, the FE, and the MEL. The new BOSS was an almost all-new power plant.
Like big-block Chevys and the Cleveland, the 385 series had canted-valve cylinder heads. the intake and exhaust valves inclined 4-5 degrees and splayed 9 degrees. As seen in the 429 for the 1968 T-bird & 460 for Lincoln.
The Mystery of the Boss 429, lies in its combustion chamber design: the valves were rotated counterclockwise around 30 degrees, mainly to improve the port angles in this hemispherical head. Also, there were usually a pair of compression pads.
Boss heads do not use gaskets. Instead, a receiver groove was machined around the circumference of each cylinder (above) to accept a ‘ Wills ring’. These rings were manufactured from a hollow metal tube around .093-.096 inches in diameter, which collapsed around .016 inches when the head bolts were torqued down, sealing the cylinder, and leaving a .010-in air gap between the head and the block. Ford experimented with variations of the setup on the DOHC Indy and Le Mans 427 engines before they were used on the Boss. It was essentially bulletproof. To seal the oil and coolant passages, receivers were also machined to accept ‘DuPont’ Viton O-rings. the ‘no-gasket’ system required much extra care during assembly,
Cale Yarborough was the first to run to victory with the Boss. It was the 1969 NASCAR season in Atlanta, driving a Wood Brothers Mercury.
With the right tune, you could squeeze 620 hp or more, from the 429 Boss. Ford ran this engine in NASCAR until 1975 when the series rules reduced the displacement limit to 358 CID, ending the big-block era in stock car racing.
To use the 429 BOSS in NASCAR like any other engine, Manufacturers had to offer the engine to the public in a standard production car.
(above) you can see the assembly line was set up in Michigan, where Ford’s private performance contractor, Kar-Kraft, put together a limited run of Boss 429 Mustangs. Only 1,358 cars were ever assembled, 859 in 1969 and 499 in 1970.
(The production run also included two Boss Cougars. See our article about those unique cars in another article here in our special interest section.)
It is no surprise these are highly sought-after collectibles.
When the NHRA overhauled its Pro Stock rules for the 1982 season, adopting a single 500 CID limit, Ford drag racers had no choice but to dust off the old Boss V8, out of regular production for more than a decade, and update it with ’80s technology.
Bob Glidden Thunderbird and Probe-based racers did this better than anyone else, winning five straight season championships from 1985 to 1989. The family-operated team took its last national event victory in 1995, and Glidden retired in 1997 with a lifetime of 85 wins and 10 season titles.
The Boss still continues to impress
Currently, Jon Kaase offers an Updated BOSS if you will. Called the Boss Nine V8 (below) naturally with Kaase’s own cylinder head castings, which feature the latest combustion and airflow technology.
The package, designed to be both powerful and practical, has been re-engineered to use the standard (and widely available) 429/460 Ford cylinder block and conventional steel head gaskets, with up to 1,000 normally aspirated hp available.
