Today is 429
 

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Every story has a beginning. This is Chapter 2: the birth of the Boss 429 Mustang. This is the prototype of the Boss 429 Mustang before the moniker "Boss 429" came about. But let's start at Chapter 1; Once upon a time . . .

Ford was enjoying it's dominance of both NASCAR and NHRA with it's 427 Cobra engine. Everything was coming up roses until an elephant showed up; Chrysler's 426 Hemi and literally took it all away from Ford. Needless to say, Ford was pissed, so new marching orders were given; beat the Hemi. This resulted in an unbelievably short gestation period; just 90 days after the 1964 Daytona 500 when Chrysler came in 1,2 & 3 . . . the birth of the 427 SOHC engine. If there was ever a result of the old adage "you can solve any business problem by simply throwing money at it" the SOHC motor definitely comes to mind.

Unfortunately Big Bill France didn't like custom made engines running in his Stock Car Racing series. He wanted production engines. But he did cut Ford a break . . . sort of. They could run the 427 SOHC, but they would have to run under a weight penalty of 10% which defeated the extra horsepower the engine made. In the 427 day thread you saw a SOHC 427 Chevy engine. Chrysler also had one based on the Hemi, just in case Ford got their way. Ford learned a valuable but expensive lesson; proper planning prevents piss poor performance when it comes to introducing a new engine into NASCAR.

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Why did Ford choose the Mustang to be the recipient of the new Boss 429 engine? It didn't fit. The shock towers had to be extensively modified to make the engine fit. There are two schools of thought. First is the newly redesigned Mustang would prove to be a huge seller so put your newest high performance engine in your newest high performance car.

The second was Ford's desire not to give the competition an easy way out to compete. The Boss 429 would fit in the Torino, the car Ford would race in NASCAR with no major issues (like the Mustang). If the Torino had been chosen, then any competitor could walk into any Ford dealership and walk out with a race car equal to Fords.

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Ford had a small problem with the Boss 429 Mustang. The car was nose heavy due to the massive engine and had handling issues. Ford tried two approaches to solve this. First; install a rear sway bar, a first for the Mustang.

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Ford's second approach was a lot more radical; mount the engine towards the back of the car instead of in the front. This did cure two issues; better handling and much less wheel spin on acceleration. But the benefits weren't enough to justify the massive investment to tool up such a configuration for a limited production car.

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Ford wanted to use the brand new Goodyear F60 series tires on both the Boss 429 and the Boss 302. Initial testing showed that standard Mustang spindles were not up to the challenge of the much wider (read: better gripping) tires so heavy duty spindles had to be made. Testing also showed that the shock towers were pulling apart from the body due to the F60s so they had to be reinforced.

The " Boss " Mustangs were the design of Larry Shinoda Japanese American

https://i.postimg.cc/4NtcQX44/autowp...boss-429-9.jpg

Motor Wheel Corp had been making the "spider" style mag wheels for Detroit ever since they were introduced on the 1966 442. MWC also sold them under their own moniker. It was Ford who used that moniker; Magnum 500 for the Boss 429 and Boss 302. Other monikers were; Road Wheels, Super Stock I, Super Sport, Mag Style Custom Wheels, etc.

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Ford lost money selling Boss 429 Mustangs. It was estimated that Ford lost about $1000 on each car. That's $7,033 in todays money and Ford built a total of 1357 Boss 429 Mustangs.

The new rule for NASCAR was; you needed to build 500 production cars with a new engine before it would be allowed to be raced. 857 in 1969 and 500 in 1970.

BTW: Those are the tires used on the 1970 Boss 429.

Thanks Lee.

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Put a brand new high performance engine in a stock car when you know your competition is developing a "homologation special (Charger 500)" - not going to happen.

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OK - Ford is back in the number one spot at NASCAR with it's Boss 429 powered Torino Talladega. What about NHRA? Mercury, Ford's sister corp. wanted a piece of the action and asked that a couple of Cougar Eliminators be given the Boss 429 treatment.

Unfortunately what works in NASCAR doesn't always work in NHRA and this proved out when the Boss 429 Cougars failed to garner the same results in drag racing that Ford was enjoying in NASCAR.

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Look carefully at the specs. Notice that Ford is calling the engine a 429 Cobra Jet HO. The car is called the Boss 429 Mustang, not the engine.

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Ford rated the Boss 429 at 375 HP which unlike the 428 Cobra Jet was probably very close to the engine's given rating. Even with the standard 3.91 rear the Boss 429 Mustang developed a poor performance rating as a muscle car compared to others. This was probably due to the choice Ford made for the carb, a 715 CFM. If Ford had used the 780 CFM carb from the Boss 302 it's performance would have been a lot better.

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Some different color choices, a black painted hood scoop and halfway through the 1970 model year Ford finally pulled the plug on the Boss 429 Mustang.

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For the 1970 model year Ford introduced a new engine; the 429. It was available in three configurations. First the 429 Cobra Jet Ram Air as seen on the Torino GT and Torino Cobra above. This engine was not available in the Mustang which continued to use the 428 CJ. Ford got a little more serious about their engine HP ratings with the 429 CJ now rated at 370 HP

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The second engine configuration was the 429 Cobra. Identical to the Cobra Jet Ram Air just missing the shaker induction system. Same 370 HP rating. Both the Cobra and Cobra Jet RA engines were optional on the Torino Cobra.

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The third engine configuration was the 360 HP 429 Thunder Jet which came standard on the Torino Cobra. 10.5 CR instead of the 11.3 CR for the Cobra and Cobra Jet RA.

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There was one more engine configuration. The 429 Super Cobra Jet Drag Pack. For the additional cost—just $155, recall—you got four-bolt caps on the middle three main bearings, forged aluminum pistons on heavier-duty connecting rods, a solid-lifter camshaft with more aggressive profile (versus a hydraulic cam fitted into the lesser 429s), a genuine Holley 4150-series carburetor flowing 780 cfm (and a functioning Shaker scoop when the J-code Ram Air engine was specified) flowing 12 percent more air, an oil cooler mounted to the radiator support, header-style exhaust manifolds, and more.

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Would it surprise you to learn that under that shaker air cleaner sits a 700 CFM Rochester Quadrajet carb? Ford was having issues with it's Autolite carbs passing the new emissions rules and went to GM to solve them.

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Not many changes for 1971 with one big exception. While all the other car manufacturers were dropping their compression ratios to meet new emission rules, Ford managed to continue offering the 429 Cobra Jet (new moniker) and Cobra Jet Ram Air with their original 11.3 CR intact.

.......

I had one of those 429 QuadraJet carburetors about a year ago. Picked it up at a yard sale.

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Another redesign for the Mustang came with the 1971 models. Bigger and heavier. The 1971 Mustang was a real porker compared to the 1965/1966 Mustangs. The curb weight on a 1966 K code Mustang Sportsroof was 2974 while the curb weight on a 1971 429 CJ Ram Air Mustang Sportsroof was 3607!

The 429 Cobra Jet and 429 Cobra Jet R (new moniker) were options on the Mustang. The 429 Thunder Jet wasn't an option. Both were again rated at 370 HP.

https://www.youtube.com/watch?v=LlKk...eature=related

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BTW . . .

Someone mentioned in the 427 day thread that coming up would be 430 and 502. I have no interest in starting a thread on either because the 430 was never used in a muscle car and the 502 is strictly an O-T-C engine available from Chevrolet. I missed 426 (rats!). Will have to wait until next year. Or . . . maybe if I am bored I can start a Belated 426 Day thread :cool2:

You also missed 421 and 425. If you do 440, 454, 455 and 460 I'm going to get worried.

I saw somewhere that the Ford 427 was actually a 425, but Ford wanted it to be called a 427. I haven't done the math to check this out.

OK - MAYBE a Belated 421 Day thread but 425 - nope. And before you bring it up, yes, next year you will see a 327 Day thread. Count on it!

It's neat how you can just make out the Mach 1 stripe on the Boss 429 prototype in the winter/spring Michigan pic.

QUOTE "Testing also showed that the shock towers were pulling apart from the body due to the F60s so they had to be reinforced."

Those shock towers caved on ALL the V8 Mustangs, even the small blocks, unless reinforced some way. All those early Mustangs were virtually impossible to keep aligned without doing some mods. Really hard on tires.