In an effort to make an indelible impression on potential customers as to how new, exciting, and desirable an automaker’s cars were, dealer brochures of the 1960s could vary significantly in style and content. Some focused on pretty pictures and flowery text to convey how each model would make buyers feel when they experienced it, but the descriptions could be light on specifics.
Others kept the daydreamer content to a minimum and got right to the point, while still including high-quality art. Literature for muscle cars and low-priced models tended to lean in that direction. Manufacturers that catered to those prospects recognized the importance of describing the equipment provided for the money spent. Just about every company pushed “value” in one form or another, however. Numerous brochures of the era also created extraordinary visual presentations through their photographs and/or renderings.
For its 1965 full-line catalog, Pontiac ticked important boxes that would appeal to its customer base, since at the time, the division seemed to be keenly aware of what the public desired in its cars. The new full-size models wore exceptional styling—the personal/luxury Grand Prix included. GTO sales were taking off like a rocket, and Motor Trend would choose Pontiac (all its models) for its 1965 Car of the Year award.
The dealer brochure, which I acquired several years ago, measures a little larger than 11 x 14 inches and features a thick and textured cover. Inside are 48 pages of art and information. There are even renderings by the famous duo of Art Fitzpatrick and Van Kaufman that depict low, long, and Wide-Track Pontiacs in exotic locales. Large body and interior pictures are also provided for each model.
The copy is fortified with useful facts, and at the back of the book there’s a thorough breakdown of engine offerings with small photos of each one, so you can even see the types of air cleaner housings and rocker covers (painted or chrome) used. Charts for transmission gear ratios, rear axle ratios, and powertrains are also included. Printed recreations of exterior color chips and a breakdown of interior choices that best match them for each model cover a full two-page spread. General specifications, options, and vehicle dimensions are found on the final page. There’s also a suggestion to pick up the 1965 2+2/GTO performance catalog to get even more in-depth specs on those muscle cars.
Pontiac went the extra mile in creating this detailed brochure that served to educate potential buyers and enable them to make wise choices when purchasing a car.
My copy has some wear and tear on it, but better (and worse) examples are still available. Currently, you can find the 1965 full-line Pontiac brochure for sale online, ranging from about $7 to $32, with the condition of the cover often playing a key role in the price. If its content is important to you, but you don’t need to hold the item in your hands to enjoy perusing it, you can search online for a free download of the brochure.
Article courtesy of Hemmings, written by Thomas A. DeMauro
The Ford Motor Company has built nearly every kind of V8 engine we can imagine over the past century, but the biggest was the 1100 CID GAA tank engine of World War II.
The GAA V8 story actually begins with a proposed Ford V12 aircraft engine (above) that was developed in the hectic days leading up to the USA’s entry into World War II. Much misinformation surrounds this engine: contrary to the campfire stories, the Ford V12 was not a copy or derivative of the Rolls-Royce Merlin engine, but an all-new design. And it was a particularly advanced one, with four valves per cylinder, double overhead camshafts, bucket-style valve followers, and an exhaust-driven turbo-supercharger. Additionally, unlike the Merlin, this engine was designed for high-volume production with a number of castings in its construction. (Ford did produce thousands of Rolls-Royce Merlin engines at its Trafford Park plant in England.)
The U.S. government declined to approve the Ford V12 for production, but not due to any particular fault of the engine, reportedly. Rather, the U.S. military planners, especially at the navy, were focused on air-cooled radials rather than liquid-cooled inline engines for aircraft use. But the Allied war effort was in desperate need of tank engines for the ground war, which was bound to be protracted and difficult, so the Ford V12 was hastily converted into a V8 (hence the 60-degree bank angle). With a bore and stroke of 5.402 inches by 6.0 inches, the V8 version displaced 1100 cubic inches (18 liters) and was nominally rated at 500 hp at 2600 rpm, with 1050 lb-ft of torque at 2200 rpm.
Ford produced the GAA and its variants (GAF, GAN, etc., and a V12, the GAC) at its Lincoln auto plant on Warren Avenue on the west side of Detroit, above. Historically, this brought the Lincoln facility full circle, if you will. Henry and Wilfred Leland had originally built the factory to produce Liberty aircraft engines for World War I.
By passenger car standards, the GAA was enormous: five feet long, four feet tall, and almost 1,500 lbs. But it was a perfect fit in the engine bay in the rear of the Sherman M4A3 tank, below, which weighed more than 71,000 lbs, sported a 76mm gun, and carried a crew of five. Various engines were used in the Sherman, including the strange Chrysler A57 we featured here.
Produced in vast numbers, the Sherman was instrumental to the Allied war effort, especially in infantry support. The GAA-series engines were used in other U.S. military tracked vehicles as well, and all told, more than 28,000 of the monster V8s were manufactured between 1940 and 1950. Experts estimate that somewhere between 500 and 1,000 of the engines are still in existence today.
Article courtesy of Mac's Motor City Gragae.
In 1935, there were no truly automatic transmissions on the market. But Hudson made an effort to offer the next best thing with a fascinating feature called Electric Hand.
This fact has been a bit mislaid by history over the years, but in its day, the Hudson Motor Car Company was a technical innovator. While the independent Detroit car maker was a fraction of the size of Ford or General Motors, with a fraction of the resources, Hudson was often able to hold its own in engineering. Advanced features in 1935, for instance, included a one-piece, all-steel top, Baker Axleflex independent front suspension, and a fascinating automated gear-shifting feature called Electric Hand. While Electric Hand was not an automatic transmission in any true sense, it’s a clever gadget that’s worthy of a closer look.
Developed for Hudson by the Bendix Corporation of South Bend, Indiana, Electric Hand was, in simple terms, a vacuum-electric pre-selector system. The transmission itself was a conventional three-speed synchronized mechanical unit, as usual. But mounted on the steering column was an electrically operated switch module with a tiny H-gate, just like a standard-pattern three-speed shifter in miniature, that allowed gear selection with the flick of one finger.
Or pre-selection, shall we say. For example: While in first gear, the driver could move the thumb lever to the second-gear position, but the gear change was not accomplished until the driver either pushed in and released the clutch pedal, or removed his/her foot from the throttle pedal and then reapplied it, which triggered a vacuum-powered clutch servo. All upshifts and downshifts could be accomplished this way, but in a patient and deliberate manner. Speed-shifting was not part of the program.
While not nearly as simple to use as a modern automatic transmission—today, we just drop the selector in D and go—-Electric Hand required considerably less physical effort and bother than a conventional transmission of the time. Also, it allowed drivers to keep both hands on the steering wheel, which Hudson smartly promoted as a safety feature. One more benefit of Electric Hand was that it got rid of the traditional shift lever in the middle of the cabin floor, allowing for real three-abreast seating in the front.
The illustration above shows the workings at the transmission end of the system. The large cylinder, powered by the engine’s intake manifold vacuum, performed the long portions of the shifting pattern, while the smaller cylinder on top pulled the shifter across the H portion of the pattern. As the drawing shows, the system worked through the transmission’s existing shifter mechanism. In fact, a conventional shift lever was furnished with the car, stowed away in the cabin, in case the Electric Hand suffered a failure.
That leads us to an amusing feature of Electric Hand: If you pull back the floor mat, install the mechanical shift lever in the transmission receiver and run the steering column control switch through the gears, you can watch Electric Hand move the big shift lever through the gears as if operated by an invisible robot hand. What fun. You can view demonstrations of this stunt on YouTube, here for example.
Electric Hand was an available option on all Hudson and Terraplane models from 1935 through 1938. However, the feature was discontinued in 1939 when Hudson, taking a lead from Buick and others, adopted a column-mounted mechanical shift lever. The column selector, which Hudson marketed as Handy Shift, negated one of Electric Hand’s key benefits—three-abreast seating. In 1942, Hudson would offer a more advanced quasi-automatic transmission called Drive Master.
The story doesn’t end quite there, however. Bendix also supplied the same basic system to Cord for use on the 810/812 front-drive models of 1936-37, where a conventional mechanical shift linkage would have been cumbersome indeed. Here the feature was marketed simply as Remote Control shifting. And since the star-crossed Tucker 48 used salvaged Cord transmissions, the Bendix system can be found there, too.
Article courtesy of Mac's Motor City Garage
Ford’s MEL V8 might not have a famous racing record, but it’s worthy of a closer look.
The Ford Motor Company had a plenty on its plate for the 1958 model year. First, there was the rollout of an entire new car division, the ambitious but unfortunate Edsel. Next, there were two distinct new big-block V8 engine families heading into production, the FE series and the MEL series. The FE (short for Ford-Edsel) went on to glory at Daytona, Le Mans, and elsewhere, while the MEL V8 (Mercury-Edsel-Lincoln) is largely forgotten today. But that doesn’t mean the MEL isn’t an interesting engine and worthy of a closer look.
Between 1958 and 1968, the MEL V8 was produced in four displacements: 383, 410, 430, and 462 cubic inches. All were built on the same basic architecture with 4.90-inch bore spacing, and they all shared the unusual design feature shown above. There were no combustion chambers in the cylinder head. Instead, the block deck was machined at a 10-degree angle, forming a wedge-shaped combustion space in the top of the cylinder bore. This unusual construction, engineered in part to provide manufacturing flexibility, was a Motor City fad of the late ’50s that was also found in the Chevrolet 348/409 V8 (read our feature on the 409 here) and Ford’s SD series large-displacement gasoline truck engines. While the MEL V8 resembles the big SD V8 in some aspects, it shares no major components with the SD, the FE, or any other FoMoCo engines—it’s a lone ranger. Applications for the MEL V8s break down as follows:
+ 383 CID: 4.30-in x 3.30-in bore and stroke, used by Mercury in 1958-60
+ 410 CID: 4.20-in x 3.70 bore and stroke, used in 1958 Edsel Corsair and Citation. Marketed as the E-475 V8 in accordance with its 475 lb-ft torque rating.
+ 430 CID: 4.30-in x 3.70-in bore and stroke, used in 1958-60 Mercury, 1959-60 Ford Thunderbird, and 1958-65 Lincoln.
+ 462 CID: 4.38-in x 3.83-in bore and stroke, used by Lincoln from 1966 to 1968, when it was replaced by the 460 CID V8 from the Ford 385 engine family and the MEL series was discontinued for good. The MEL and 385 engine families share 4.90-inch bore centers, suggesting that the 385 was designed to run on the MEL’s tooling.
As we’ve seen, Ford wasn’t afraid to try new things in this period. For example, check out the elaborate engine shroud with thermostatic air intake shown above left on an Edsel E-400 V8 (361 CID, FE series). While a press photo was released, it doesn’t seem the remarkably modern-looking engine cover ever made it into production. (We haven’t seen one, anyway.) However, we can see that the production Edsel engines (410 CID E-475, above right) did use thermostatic air control, ducting exhaust heat into the air cleaner housing.
Despite its multiple virtues, the MEL V8 never gained a foothold in the high-performance world. Its exploits in racing were few but noteworthy: Johnny Beauchamp’s 430-powered ’59 Thunderbird nearly won the 1959 Daytona 500 in the famous photo finish with Lee Petty, while the team of Rodney Singer and Karol Miller took Top Eliminator honors at the NHRA Nationals in Detroit in 1959 with their Lincoln-powered dragster.
Among production MEL V8s, the ultimate in looks and muscle might well be the 1958 Mercury Super Marauder, a special package with three two-barrel Holley carburetors and a fabulously styled cast-aluminum air cleaner assembly (below). With 400 hp at 5200 rpm and 480 lb-ft of torque at 3200 rpm, the 430 CID beast is easily among the most powerful engines offered by the Motor City in the ’50s.
Article courtesy of Mac's Motor City Garage.
Most gearheads will instantly recognize the familiar GMC 6-71 blower, but its original application and backstory remain relatively unknown. Let’s explore.
The GMC blower of history and legend is, of course, a type of pump known as a Roots blower. Two brothers, Philander and Francis Roots of Connersville, Indiana (no relation to Rootes of Great Britain; note the spelling) initially devised their machine in the 1850s to pump water, but it has countless applications for moving fluids and gasses, from underground mines to blast furnaces. In common use, a Roots blower can be as small as a matchbox or as big as a house.
One interesting aspect of the Roots blower is that its internal flow is the opposite of what we may imagine: around the outside of the rotors or impellers (above right). In automotive applications, a Roots blower typically has two, three, or four lobes per rotor (the GMC uses three in its original form). The Roots is a positive-displacement pump. That is, with each rotation it will pump its approximate displacement. When pumping air, it’s one atmosphere in and one atmosphere out with each turn of the rotors. There is no net internal pressurization in the blower itself.
The concept of supercharging is essentially as old as the automobile. Obviously, if we can pump more air through an engine at a given speed, we can burn more fuel and make more power. Numerous types of pumps are suitable for the job, including the Roots blower, and Mercedes was the first to offer a Roots blower on a volume production vehicle with its Kompressor models in 1921. But there were many others to follow, including Bugatti, Bentley, and Maserati.
A small but noteworthy point: Since the Roots is a positive-displacement device without internal pressure, supercharging is achieved by using the blower to pump more air than the engine can, thereby raising the air pressure in the intake manifold above atmospheric. For this reason, some insist that the Roots blower, unlike most other types, is technically not a supercharger—even though supercharging is the ultimate result. If we call the machine a Roots blower, everyone can be happy.
Above is the GMC 6-71 blower in its original habitat: mounted on the side of a GMC Detroit Diesel 6-71 engine. Introduced in 1938 and produced well into the 1990s, the 6-71 is a two-stroke, six-cylinder diesel. In GMC diesel nomenclature, 6 represents the number of cylinders, while 71 represents the cubic-inch displacement per cylinder. So the displacement here is 426 cubic inches, and that is the approximate displacement of the blower as well. The 71-series has been produced in versions of one to 24 cylinders, and each one has a blower (or blowers) of appropriate size. Here the blower does not serve as a supercharger but simply as an air pump. Since the 71 series is a two-stroke, the blower is used to pull in fresh air and push out the spent exhaust gas.
As we saw earlier, Roots blowers were originally found only on the most exotic and expensive cars—beyond the reach of the backyard mechanic. But that changed in 1948 when pioneer hot rodder Barney Navarro mounted a war surplus GMC 3-71 blower on the flathead V8 roadster he raced on the California dry lakes. Others followed, and now thanks to General Motors, hot rodders had an affordable and plentiful supply of Roots blowers in a number of sizes, including 3-71, 4-71, and the 6-71, the latter being perfect for the new overhead-valve Detroit V8s. Regardless of size, all the GMC blowers have the same authoritative sound, somewhere between a growl and an angry whine.
Soon enough, the ever-inventive hot rod industry developed a number of adapters and drive systems, including gears, chains, multiple v-belts, and the most popular setup, the toothed Gilmer belt. Aftermarket cases, rotors, end plates with sealed bearings, and other parts also appeared, and complete turn-key kits as well. (Above, Weiand kit at left and Dyers kit at right.) There were also front-mount kits from Potvin, Cragar, and others (see below) that echo the original Blower Bentley setup, though the conventional top-mount system with Gilmer belt proved to be more practical.
In ’70s drag racing, the 6-71 size gave way to 8-71 and larger blower displacements and today, NHRA racers in Top Fuel and Funny Car use blowers of extrapolated 14-71 dimensions as defined by the current rules. On a 6-71, the impellers are not quite 15 inches long while the 14-71’s are a full 19 inches in length. But the design itself is based on the original GMC two-stroke blower.
To tell the truth, these days the GMC 6-71 blower is increasingly obsolete as a performance booster. There are newer and better alternatives including the turbocharger and the Lysholm twin-screw supercharger (which resembles a Roots blower but isn’t). Still, hot rodders continue to embrace the venerable 6-71. For looks and sound, it’s difficult to top.
Article courtesy of Mac's Motor City Garage.
We’re seeing many hot rods with great looking drilled and/or slotted rotors behind big billet as well as forged wheels. There’s no question that they look trick, but what is the straight story on how they work? Are they better than plain rotors, or worse? In the real world of street driven cars, will they help my stopping power? Rather than listen to a lot of opinions, let’s look at the science behind these questions by getting info from the experts at Wilwood brakes and ECI.
Mike Skelly of Wilwood offered us a little history on the origin of drilled rotors. As road racing tires allowed greater track speeds in the 1960s, race teams began seeing a great loss in brake capability. In that era of organic and asbestos based pad friction material, a problem occurred with the adhesives used to fasten the pad to the steel backing plates. As the temperature of the pads increased, the adhesive would break down and cause a layer of gas to form between the rotor and the pads. That vapor layer retained heat in the rotor and acted as an “air-bearing” high-pressure area between the pad and rotor. By drilling holes in the rotor surface, those gasses were able to be dissipated into the vented center of the rotor, no longer interfering with the pad to rotor friction. Racers also liked the idea that the rotating mass of the rotor was reduced, causing a small advantage of less inertia during acceleration and braking.
Slotting the rotor is felt to have its greatest effect removing worn off pad debris from the rotor surface. The relatively sharp edges of the slots are also considered as an aid in resolving the pad glazing that can occur at high temperatures. Fresh pad material is then exposed for better braking action at the cost of faster pad wear due to the constant renewing of the pad surface. The conclusion is that slotting may improve braking, with little chance of loss.
Since asbestos based brake pads were outlawed in the nineties, new materials and bonding adhesives have been developed. The now common ceramic based pads do not produce the outgassing problem in any conceivable street use, so there is no real function-based reason to use drilled rotors. Slotted rotors may still be useful in their ability to remove pad glazing but consequently produce faster pad wear. That spells more brake dust on your wheels, which can be corrosive to aluminum wheels, as are many of the chemical cleaners used to remove that dust. Since most hot rods are not driven hard enough to get hot enough to glaze the pads, slotted rotors may offer little in the way of better brake function.
Heat damaged brake rotor
It’s important to recall that a major function of the rotor is to transfer heat out of the brake system. The laws of Physics tell us that energy can be moved and converted to other forms of energy, but never destroyed. That means the kinetic energy (rotating mass) of the rolling wheel and tire are resisted by the brakes, which convert that motion energy into heat energy. That heat is then dissipated into the air by the cooling of the caliper body and rotor. Think of the rotor as the radiator for the brake system. That’s why brake fluids with higher temperature tolerances were developed, and why vented rotors are common today.
Following that heat transfer logic tells us that a rotor with more mass can absorb more heat energy than a lighter rotor of the same design. That is an advantage of larger diameter rotors, along with the greater leverage of increased size. The problem with regard to our question of drilled and slotted rotors is that those practices act to reduce the mass of the rotor, reducing the desired heat transfer. Some rodders have correctly stated that the rotor surface area is increased by drilling or slotting, but the issue in heat transfer is mass, not surface area. It does seem that a greater rotor surface area may allow a faster cool down after the heavy braking has stopped, but the issue is more about heat transfer during braking due to rotor total mass.
It is the experience based opinion of every single brake expert I have consulted, that the loss of rotor mass due to drilling and slotting creates more brake loss than any possible gains due to degassing or faster cooling of the surface area. There is no better authority on hot rod brakes than Ralph Lisena at ECI. Ralph agrees that practical street driven vehicles rarely encounter the high heat conditions that make drilled or slotted rotors beneficial from a strictly functional stand point.
For the street, you want a heavier, larger diameter rotor. As a case in point, the ’73-’87 Chevy pickups offered a light duty one-inch thick front rotor, and a heavy duty option that was one and a quarter-inch thick. Since both were ttwelve-inchdiameter cast iron vented rotors, using calipers of the same piston bore and using the same pads, the conclusion we draw is that GM engineers agreed that the larger rotor mass would produce the desired better brakes for heavier loads.
So we seem to be back to the idea that the major issue in brake system heat transfer is the rotor mass. Outgassing of heated brake pads is not an issue in any conceivable street application. Therefore, drilling the rotors may cause a very small loss of braking power, rather than an increase. But, we may be over thinking a small issue. The consensus among experts is that there will be little effect either way in the real world. So, if you like the way they look, go for it. You’ll have the racy look, and the car should stop just fine. In fact, I just got thirteen-inch Wilwood rotors for my own ’57 Chevy “Smokey Yunick” Tribute AutoCross car. I’ll run it hard in the Goodguys AutoCross series, so we’ll take Wilwood’s advice to run slotted, but not drilled rotors.
Article courtesy of Goodguys Rod & Custom Association, written by Brent Vandevort.
Between 1956 and 1964, the carmakers of the Motor City had a brief but serious fling with push-button driving.
Today we look back on the 1950s as a quiet time, but there was plenty enough going on. After all, the ’50s managed to include the Jet Age, the Atomic Age, the Television Age, the Push-Button Age. Change was upon us. And with pushbuttons, now every convenience of mid-20th century life was right at our fingertips. Or at least that was the theory, as suddenly all our gadgets from televisions to kitchen appliances were sporting push-button controls. And sure enough, the push-button fad quickly jumped over to the auto industry in 1956, when the Chrysler Corporation adopted push-button gear selectors for all its passenger cars.
But just to illustrate that seldom is anything new in the car business, this wasn’t the first push-button gear selector. Way back in 1914, the Vulcan Electric Shift was adopted by Haynes, Pullman, and a few other carmakers. The Vulcan system, which used column-mounted pushbuttons and a series of solenoids to actuate a conventional manual transmission, proved to be a flop and was immediately withdrawn from the market. Which brings us to 1956.
While Chrysler wasn’t the only carmaker to offer it, as we shall see, it was by far the major promoter of the push-button gear selector, offering the feature on all its automatic-transmission cars from 1956 through 1964. A ’56 DeSoto is shown above, but all the Chrysler brands used similar controls on the left side of the dash—Plymouth, Dodge, DeSoto, Chrysler, Imperial. There were various names; Dodge called its version Magic Touch.
While a number of button arrangements (horizontal, vertical, diagonal) were used through the years, the controls were all mechanical, with a steel push/pull cable between the shifter assembly in the dash and the Powerflite (two-speed) or Torqueflite (three-speed) transmission. Note that originally, there was no P for Park. Chrysler later added an internal parking pawl mechanism to the transmission and a dash lever to operate it.
While the selector worked perfectly fine, it was dropped by Chrysler for 1965 in favor of a conventional column (or floor) lever. There are many theories as to why, but strictly from a product perspective, we can see that over time, the feature progressed from innovative to novel to merely odd. It didn’t seem to attract many buyers at the end, but it may well have discouraged some. In Chrysler advertising, the feature had all but disappeared a few years earlier.
Packard also stepped up with a push-button gearchange in 1956, which it called the Electronic Selector. Standard on the flagship Caribbean and optional ($52) on the rest of the Packard line, it mounted to the steering column on a stalk, above. Unlike the Chrysler system and just as the name indicates, the Packard system, supplied by Autolite, was electrically operated rather than mechanical, with a beefy 12-volt motor to rotate the transmission’s hydraulic shift valve. And going Chrysler one better, Packard included a Park button. When the Detroit-built Packards were discontinued at the end of the ’56 model year and production moved to South Bend, Indiana, that was the end of the Electronic Selector as well.
Introduced on E-Day, September 4, 1957, the 1958 Edsel featured a push-button gearchange that was branded as Teletouch Drive. Like Packard’s, the Edsel system employed an electric motor to shift the automatic transmission’s gears, but with the added innovation (headache, some would say) of steering wheel-mounted buttons. Alas, Teletouch had a few bugs in it, an especially painful problem in the launch of a bold new product like the Edsel. The feature was dropped for 1959.
Even little American Motors got in on the act with a push-button dash control for the top-of-the-line Rambler Ambassador. Called Telovac and developed by Borg-Warner, which also supplied AMC with its Flash-O-Matic automatic transmissions, the feature was offered from 1958 to 1962. Like Chrysler, the Rambler used a separate control for Park.
Ford’s Mercury division joined the push-button crowd with a straightforward system called Keyboard Control, then upped the ante for 1958 with the elaborate setup above. Multi-Drive Keyboard Control, as it was called, included two drive ranges, “performance” and “cruising,” along with a hill-control feature for the Merc-O-Matic transmission. Multi-Drive was continued in 1959, but the push-button dash console was replaced with a traditional column-mounted lever.
It’s interesting to note that while the Mercury and Edsel divisions of the Ford Motor Company gave pushbuttons a try, the Ford and Lincoln divisions never did. Until recently, that is: The 2018 Lincoln Navigator shown below sports a dash-mounted push-button array. Now that automatic transmissions are fly-by-wire with no mechanical linkage, pushbuttons make more sense than they ever did. (The user interface can be anything: buttons, a dial, an icon on a touchscreen.) In this form, we’ll probably be seeing pushbuttons for many years to come.
Article courtesy of Mac's Motor City Garage.
Even though it was developed more than 60 years ago, the Ford 9-Inch is the rear axle of choice throughout the American high-performance world. Here’s why.
When the Ford Motor Co. unveiled its 1957 vehicle line in October of 1956, in the press materials there was only brief mention of a new rear axle assembly for its cars and light trucks. Engineered in-house and produced by the company’s Sterling Axle Plant on Mound Road, which had opened only a few months earlier, the axle proved to be a winner—beyond anyone’s wildest dreams, actually. At the time, no one could have foreseen that today, more than 60 years later, the Ford 9-Inch is ubiquitous all across the American racing and performance scene.
The exploded diagram above reveals many of the design features that made the 9-Inch so popular:
+ The carrier housing is a front-loading dropout type, also known as a “banjo” or “pig” style, which is far more mechanic-friendly than the more common Salisbury/Spicer design in which the differential carrier loads into an integral axle housing from the rear. Here, backlash and pinion-depth adjustments are quick and easy, and gear ratio changes can be accomplished in minutes.
+ The pinion-shaft assembly is carried in a separate, detachable sub-housing (a cartridge, as some describe it), which simplifies adjustments even further and allows beefy, large-diameter bearings and yoke.
+ The axle shafts are secured in the housing with sturdy retainer plates at the housing ends, rather than with C-clips inside the carrier, a setup that is not terribly safe or suitable for serious racing use.
+ The ring gear (crown wheel in the Queen’s English) is a generous 9.0 inches in diameter, which allows the axle to withstand extreme torque loads and lent the rear axle its familiar name. Ford also manufactured axles of this design with 8.0-inch and 9.38-inch ring gears for various applications, and at one time or another, the axle family has been used in virtually every U.S. car and light truck platform produced by the company between 1957 and 1986.
So by fortune or design, the 9-Inch checks a number of important boxes for high-performance use. And when we dig a little deeper, we can see even more significant advantages, starting with a property called hypoid offset, above. In the hypoid gearset, introduced by Packard and Gleason Gear Works in 1926, the pinion gear is offset from the ring gear’s centerline, rather than centered as on a conventional spiral-bevel gearset. The result is a sort of bevel/worm gear hybrid, combining both meshing and sliding action between the gear teeth, and the increased contact area produces a stronger, quieter gearset. (Hypoid axles also allow a lower driveshaft and flatter passenger floor, surely the main reason they were embraced by the American car industry.)
In most U.S. passenger car drive axles, hypoid offset is generally in the 1.25-in. range (top left gearset). But on the Ford 9-inch (lower left gearset) the offset is much greater: 2.38 inches. This provides an even longer, deeper tooth contact (yellow arrow). The increased contact area does come at some cost: greater friction, more heat (often requiring a differential cooler), and a small but significant increase in mechanical loss— around two percent. In most applications, racers find the sacrifice is more than worth it. But it’s surely no coincidence that the 9-Inch was discontinued on production cars when fuel efficiency became a prime concern.
One more advantage of the 9-inch worth mentioning, as indicated by the red arrow above: Unlike most every other unit of its class, the Ford carrier includes an extra journal on the nose of the pinion to support a bearing set deep in the case, which stabilizes the gearset against deflection and allows a shorter, more compact pinion shaft.
With all these valuable attributes, the Ford 9-inch is far and away the favorite of the American high-performance scene, from street rodding to NASCAR, and it has been for decades—despite the fact that Ford hasn’t offered the unit in a production vehicle since 1986. Every component, down to the last spacer and seal, is now available in the performance aftermarket. Like a small-block Chevy V8 or a Fender guitar, an entire 9-inch axle can be assembled without a single original factory part. Specialist suppliers including Strange, Mark Williams, and Moser Engineering (shown above) offer a complete range of components and assemblies for every conceivable purpose.
It may seem a little odd that one of the top racing series in the world depends on a major component that was developed more than 60 years ago, but it’s true: Every car that runs in NASCAR Cup today has a Ford 9-Inch rear end under it—yes, even the non-Ford entries. As a result, the NASCAR teams have amassed vast inventories of 9-Inch assemblies, as shown below, in every gear ratio you can imagine, for tracks from Martinsville to Talladega.
But the way we hear it, that may be changing soon. Reportedly, NASCAR will ditch the venerable 9-Inch on the next-generation Cup car due in 2022 and adopt a sequential transaxle similar to those used in the Australia Supercars Championship. Still, we know that the Ford 9-Inch will be around the performance world for decades to come.
Article courtesy of Mac's Motor City.