Login to your account
Not a member? Register now.

Subscribe To The Blog:

Follow Us

The Latest News And Reviews
Throughout The Car Industry

The 1969-70 Boss 429 Mustang

Comments: Leave | View
On: Mon, Sep 26, 2011 at 3:35PM | By: Peter C Sessler

The 1969-70 Boss 429 Mustang

Ford built quite a few special cars during the 1960s. Some were built by others for Ford—the Shelby Mustangs are probably the best known of these. But, by 1968, Ford decided that they could build these types of cars themselves. They would be able to exercise more control, build a better product, and, quite possibly, save some money in the process. Since most of the cars had something to do with racing one way or another, the end result would be greater showroom traffic and, thus, more sales. After all, this was the reason Ford was doing it all.

The Boss 429 was a bit different. The Boss 429 was an engine that was to be used in the NASCAR races, not a car. Still, in the end, Ford decided to use the engine in a special Mustang and call that Mustang Boss 429 as well.

Everyone nowadays thinks of NASCAR as a giant of motorsports—which is true. NASCAR is a giant of motorsports today, but that was not the case in the late 1960s. Stock car racing was popular, but only in the south. The prime competitors were Chrysler and Ford. The Boss 429 was to take over from the Ford 427 and give the Chrysler 426 Hemi a run for its money—which the Boss 429 definitely did.

Yet, the popularity of the Boss 429 was limited, at best. It was known in the south, but that was about all. It was an expensive car to build, and it is quite likely that Ford lost money on every car it built. After all, Ford was building the Boss 429 only because NASCAR said that at least 500 had to be built and, this time, Ford and other manufacturers couldn’t cheat their way past the rules. So the Boss 429 was built and, in spite of all the interesting prototypes that were built, none reached production. Production of the Boss 429 ceased in early 1970 (January 6, 1970) with production reaching 859 in 1969 and 499 in 1970.

But what a car the Boss 429 was! Here was a car that was unequalled in so many ways. Even the 1965-66 Shelby GT350 wasn’t so unique.

The engine is what made the Boss 429 unique. The engine was a high performance version of the 429/460.

The cylinder heads are what made the Boss what it was. The heads were cast in aluminum and, upon closer inspection, it will be noted that every bolt hole, oil and water passage, are perfectly round. That is because the cylinder heads did not use conventional head gaskets; the heads were sealed with copper “O” rings while the oil and water passages with sealed with rubber Viton “O” rings.

All street Boss 429s came with an aluminum dual-plane high-rise type of intake manifold and a 735 CFM Holley four-barrel carburetor. The cast iron exhaust manifolds of the Boss 429 were also unique, made to fit within the tight confines of the Mustang engine compartment.

The end result was a rather tame version of the Boss 429 engine. The stock camshaft wasn’t setup to take advantage of the large porting; the heavy valves limited rpm potential; the carburetor, at 735 CFM, was small. It was up to the owner of the car to take over, but given the pressure of collector car ownership, it is unlikely that more than a few have done so.

Driveline and Interior
Just as the Boss 429 engine was unique, so was the rest of the car. The modification work was performed by Kar Kraft, a Ford subsidiary.

The major work done was to widen the engine compartment for the Boss 429 engine. At the same time, the suspension mounting points were made one inch lower and one inch wider, for better handing. This necessitated a shorter upper “A” arms than other 1969 Mustangs.

At the front, a .94 inch diameter anti-roll bar was used; at the back, a .75 inch bar was used for the first time in a Mustang. On 1970 cars, a .62 inch bar was used in the back. Coupled with 15x7 inch wheels and Goodyear F60x15 tires, this resulted in a Mustang that handled. It was the first car to use these large (for 1969) tires.

Other standard features include the following:

• Larger alternator pulley

• Engine oil cooler

• Power steering with a different valve

• Front spoiler

• Functional hood scoop

• Battery in the trunk

The rest of the Mustang also benefited from the Boss 429 treatment. In the interior, the Deluxe appointments were standard in 1969 (optional in 1970). It included special door panels with simulated wood, special wood grain dash, console, rim-blow steering wheel, special weave pattern seats and other deluxe Mach 1 appointments.

Today, the Boss 429 is one of the most sought-after 1st generation Mustangs, and that includes most Shelby Mustangs.

Photo Gallery (click a thumbnail to enlarge)


Be the first to leave a comment.

Leave A Commment

Allowed HTML tags: <a href=""> <abbr title=""> <b> <em> <i>
Please no link dropping, no keywords or domains as names; do not spam, and do not advertise! rel="nofollow" is in use