1969 FORD MUSTANG BOSS 429 - was a high performance Ford Mustang variant offered in 1969 and 1970.The Boss 429 (also known as the 'Boss 9' by enthusiasts) is arguably one of the rarest and most valued muscle cars to date. In total there were 859 original Boss 429s made. The origin of the Boss 429 comes about as a result of NASCAR. Ford was seeking to develop a Hemi engine that could compete with the famed 426 Hemi from Chrysler in NASCAR's Sprint Cup Series (then known as "Grand National Division"). NASCAR's homologation rules required that at least 500 cars be fitted with this motor and sold to the general public. After much consideration, it was decided by Ford that the Mustang would be the car that would house this new engine. The Boss 429 engine was derived from the Ford 385 engine. It used four bolt mains, a forged steel crank and forged steel connecting rods. The engine featured aluminum cylinder heads, which had a modified Hemi type combustion chamber which Ford called "crescent". These heads used the "dry-deck" method, meaning no head gaskets were used. Each cylinder, oil passage and water passage had an individual "O" ring style seal to seal it tight. The Boss 429 engine used a single Holley four barrel carburetor rated at 735 CFM mounted on an aluminum intake manifold that flowed well for its time. 1969 cars featured a hydraulic lifter camshaft while 1970 models got a mechanical lifter camshaft along with an improved dual exhaust system though rated power output stayed the same.
Tony Stewart smiles as he sits in his car before qualifying for Saturday's NASCAR Bank of America Sprint Cup series auto race at Charlotte Motor Speedway in Concord, N.C., Thursday, Oct. 9, 2014. (AP Photo/Terry Renna)
The casket of race car driver Kevin Ward Jr., is taken from a hearse before being carried into South Lewis Central School before a funeral on Thursday, Aug. 14, 2014, in Turin, N.Y. Ward died after being struck by NASCAR driver Tony Stewart's car during a race last weekend at a dirt track in western New York. (AP Photo/Mike Groll)
NASCAR CEO Brian France, left, and NASCAR president Mike Helton, right, watch a video after France's grandmother, Anne Bledsoe France, was awarded the Landmark Award for the NASCAR Hall of Fame during an announcement in Charlotte, N.C., Wednesday, May 21, 2014. (AP Photo/Chuck Burton)
Kurt Busch boards a helicopter to begin his trip to Charlotte for tonight's NASCAR race after he qualified on the first day of qualifications for Indianapolis 500 IndyCar auto race at the Indianapolis Motor Speedway in Indianapolis, Saturday, May 17, 2014. (AP Photo/Darron Cummings)
FILE - In this April 28, 2014, file photo, NASCAR driver Kurt Busch stands in front of his newly-unveiled IndyCar entry for the Indianapolis 500 during an announcement in Indianapolis. On Memorial Day weekend, NASCAR's bad boy is trying to own the title of baddest man on the track by pulling off racing's version of an IronMan triathlon. In a single day, he'll try and race in the Indianapolis 500 and the Coca-Cola 600, with a race or two against the clock thrown in. (AP Photo/Michael Conroy, File)
In this photo taken on April 24, 2014, race car driver Kurt Busch jogs to his girlfriend's home after an early morning workout at a gym in Ellicott City, Md. On Memorial Day weekend, NASCAR's bad boy is trying to own the title of baddest man on the track by pulling off racing's version of an IronMan triathlon. In a single day, he'll try and race in the Indianapolis 500 and the Coca-Cola 600, with a race or two against the clock thrown in.(AP Photo/Patrick Semansky)