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The Chrysler Road Rockets - Part 2

When the big block became King of the Street.

By Dusko Mackoski

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The decade of the 1960's encompassed many trends and significant events that would shape the future of the American automotive industry. Yet it was to be one single factor that would come to dominate and remain a defining feature of that decade: a fascination with power and speed. The market was very youth oriented and demanded high-performance machines that could run the quarter mile in under 15 seconds. Speed sold cars as America's major manufacturers came up with innovative designs to capture the performance market. Engineers developed what came to be known as "Muscle Cars," with monster big block engines. Ford began with the 406, Chevrolet had its 409, Pontiac designed the Super Duty, and Chrysler created the Max Wedge and followed it with the legendary Hemi 426.

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The influence from European sports cars saw the birth of the American "pony car" - the compact sized sports car that would quench the youth market's thirst for sports styled and good handling cars. However the trend soon shifted towards ultimate speed, and the amalgam of the pony and muscle car resulted. Designers modified chasses and used innovative materials such as aluminium, fibreglass and plexiglass to make the cars lighter off the starting line. The unique engineering and design created a phenomenon unmatched in world automotive history.

By 1970 the muscle cars popularity had reached a peak. This was to be the year all the stops were pulled and the big block became King of the Street. The stage was set for an all-out war between the manufacturers. With great pride at stake, no less than ten different asphalt bruisers were cruising the streets. The assortment of exotic machinery ranged from the 1970 SS454 Chevelle, 1969 Shelby GT-500, 1970 Oldsmobile 4-4-2 W30, 1969 ZL-1 Camaro, 1970 Buick GS Stage 1, 1969 Boss 429 Mustang, 1970 Challenger R/T and 1970 Hemi 'Cuda, just to name a few.

All could pull a quarter mile time of less than 14 seconds, with some dipping in to the 12's when fitted with slick tyres.

1970, The New Generation Barracuda and Challenger are Born

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The old generation Plymouth Barracuda had proved to be too small to accommodate the fitment of Chrysler's whole range of driveline packages. Along with this, its styling was also becoming a bit outdated due to its Valiant origins. But a new fresh design with a completely re-engineered chassis was on the drawing board - it was a necessary exercise as the market was seeing more and more big blocks cruise the streets.

There was considerable pressure from top management to get the new platform to conform to the new muscle car trend. As the Barracuda had previously fallen short of its competition, Chrysler was determined that would not happen with this model. It was dubbed the E-body and for the Plymouth engineers designing the new car, there was only one absolute brief; the engine compartment had to be large enough to accept any available engine. (Don't you wish that cars today were designed with that spec in mind?) The engines ranged from the laughable Slant Six to the 440 cubic inch big block without sacrificing power steering, air-conditioning or any other accessories. The cowl from the larger B-body cars like the Road Runner was borrowed and used for the new chassis. Once management had approved the layout of the car it was passed on to Plymouth Styling to design the outer skin.

It was at this point that Chrysler management decided to offer the platform to Dodge. Chrysler wanted an up-scale version of the Barracuda, in the same way that the Mercury Cougar was an up scale Mustang. I guess you can compare that to the Clubsport and Grange offered by HSV; basically the same car, yet different markets. And so Dodge started work on a longer wheelbase E-body that would become the Challenger.

Finally, both Dodge and Plymouth had a ponycar to sell to the youth of America. But you couldn't call them ponycars any more; they were grown-up, fully-fledged stallions. In fact, musle cars to mix it up with the best of them.

For the uneducated, at first glance the bodies of the Challenger and Barracuda look identical. Yet, no body panels are shared between the two cars. The Dodge designers chose to widen their car by flaring out the character line that copies the upper boot-line profile from the leading edge of the fender to the end of the quarter panel. Another styling cue was the "Coke bottle" effect in the rear quarter. The Challenger was given a more up-scale look by using more chrome than the Barracuda. Dual headlights were used in the Challenger's nose instead of the Plymouth's larger single units.

The Chrysler cars were both offered in hardtop and convertible with several different styles of each available, including performance versions of the hardtop, sports hardtop and convertible. Plymouth's performance badge was again the 'Cuda and Dodge used the R/T (Road & Track) name made famous by its other model lines. These cars were not just base models with badges and stripes. The 'Cuda and R/T had body reinforcement in key areas and beefed-up suspension and drivetrains to take the power and weight of the big blocks. The Hemi hardtop cars were in fact convertibles (which had a stronger chassis) with the roof welded on.

Exterior & Interior Trim

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Both companies used some of the most radical and exciting advertising campaigns - some refer to their ponycar range as the Rapid Transit System or the Scat Pack. For Plymouth's Rapid Transit system and Dodge's Scat Pack, the youth market was enticed by some of the grooviest colours seen on the street. Banana, Plum Crazy, Light Green Metallic and Lime Light are just some of the colour choices that scream out Seventies style!

Dodge offered two distinct versions of its car, namely the Challenger and Challenger R/T. Both were available in three models; hardtop, convertible and Special Edition (SE). The trim level was basically determined by the particular model of the car. But then - in the 70's - you could pretty much option any model with any extra that was available from that manufacturer. The base Challenger was equipped with a vinyl interior and bucket seats, three-spoke wood-grained steering and instrumentation that included a speedo with four other gauges. R/T models came with a Rallye Cluster consisting of a wood-grained panel that featured a 150 mph speedo, tachometer and oil pressure gauge. The SE was fitted standard with a vinyl roof. Why? I guess it looked good at the time. The SE also had a small overhead console with warning lights for door ajar, low fuel and seat belt. If a mono AM radio was fitted there was only provision for one speaker in the centre of the dash. If a stereo radio was fitted, there was provision for a speaker at each end as well. I hear what you are thinking, who needs stereo when you got four hundred and forty cubic inches of orchestra playing right before you?

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The Plymouth guys offered three styles of their car: Barracuda, Gran Coupe and 'Cuda, with the hardtop and convertible models being available in all three. The base Barracuda and Gran Coupe were outfitted in a similar way to the Challenger and SE models, although the designers saw fit to make the vinyl roof an option and not a standard feature. The 'Cuda name was reserved for the top of the range sports model, outfitted with similar gear to the R/T.

A feature of both car's design was a pair of windshield wipers that were recessed and hidden under the hood. Most car makers today still don't realise the aerodynamic - not to mention the styling - benefits this offers. To contribute to the smooth body styling of the cars, they also had flush-fitting door handles.

Several different bonnets were offered in 1970. The standard hood was almost flat, with a moulded peak running down the centre. An option on other models but standard for the R/T and 'Cuda was the Power Bulge hood. This large power bulge really gave the impression of a large engine underneath and contained two air intakes which were not connected directly to the air filter. The other option was the Shaker hood scoop which was mounted directly on the engine intake and stuck up through the hood. According to Chrysler, this "Puts on a song and dance right before everyone's eyes"!

Other goodies on offer were two different road wheels and a multitude of go-fast stripes and decals, among which was the famous bumblebee stripe. It was so named because it consisted of a pair of vertical stripes along the back of the car, resembling the abdomen of a bee. And if at this point you are thinking these cars were dinosaurs, here are some options that many of today's cars still do not have: cruise control, power windows and racing mirrors!

Chassis & Brakes

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The size difference between the two cars wasn't that great. The Dodge rode on a 110-inch wheelbase while the Plymouth's was 108 inches. The total length was 191.3 inches and 186.7 inches with a width of 76.1 and 74.7 respectively for the Challenger and Barracuda. Their weight is typically over 3,800 lbs (1700kg).

Under the skin everything was traditional Chrysler unibody, with torsion bar front suspension and independent lateral, non-parallel control arms with an anti-roll bar as standard on the performance (R/T and 'Cuda) cars. The rear suspension consists of a live axle on asymmetrical semi-elliptical leaf springs. A rear anti-roll bar was optional. Some occupant safety features were present - driver and passenger door side impact beams and a collapsible steering column.

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Drum brakes were standard and measured 10 x 2.5 inches front and rear, or 11 x 3 inch front and 11 x 2.5 inch rear on the road-racing oriented R/T and 'Cuda. There was also an option of front 10.75 inch vented discs with single piston callipers. These discs were of a two-piece design which tended to warp under heavy use but returned to normal after cooling. This problem was not fixed, and so continued until the start of the 1973 model year.

Transmission & Powertrain

Nine different engines were available in the two cars and all could accommodate accessories like air conditioning, power brakes and powersteering - even with the biggest engines (although some multi-carb engines had to do without air con). The table shows the available engines with their common name, capacity and horsepower ratings including the 340 Six Pack of the Trans-Am racing specials.

Name Size (cu. in.) Size (cc) Type Induction Power, BHP(kW)
Slant 6 225 3688 6 CYL. 1 bbl. 145 (108)
Small Block 318 5212 LA V8 2 bbl. 230 (171)
Small Block 340 5573 LA V8 4 bbl. 275 (205)
Six Pack 340 5573 LA V8 3 X 2 bbl. 290 (213)
Big Block 383 6277 B V8 2 bbl. 290 (213)
Big Block 383 6277 B V8 4 bbl. 330 (242)
Magnum 383 6277 B V8 4 bbl. 335 (246)
Hemi 426 6982 RB V8 2 X 4 bbl. 425 (315)
Magnum 440 7212 RB V8 4 bbl. 375 (275)
Six Pack 440 7212 RB V8 3 X 2 bbl. 390 (286)

The top of the range engines that made the 70's muscle cars famous for what they are were the 426 Hemi and the 440 Six Pack. These were serious horsepower producing motors. The 440 cubic inch V8 engine produced 480 lb-ft of torque at 3200 rpm in its standard form. When topped off with a trio of Holley 2-barrel carburettors, its torque output was equal to the mighty 426 Hemi. In modern speak, that's more than 670 Nm of torque; enough to very easily light up the pair of what we'd now refer to as 14 inch trailer tyres...

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However, the 426 cubic inch Hemi was by far the more technically superior engine. This was clearly demonstrated by its ability to produce more power from less cubes and be able to rev quite high in the process. Featuring a 10.25:1 compression ratio and top-mounted spark plug locations, its main characteristic was the hemispherical combustion chamber which resulted in more efficient charge mixing and hence more power. The twin carbs were staged such that, the second would come on-line only when the hammer was dropped. With both carbs on full noise, there was enough flow to make a fire hose look like a McDonalds drink straw.

By far the most popular engine options were not the full-on, race-spec 426 Hemi or the 440 Six Pack. These were considered exotic but gave the young men of the time something to dream about. (Somebody mention the HSV GTS 300kW?) This was evident in the sales figures, clearly showing that over the cars' lifecycle, the Hemi and 440 Six Pack sales were only in the hundreds rather than thousands. The big block 383 and small block 340 were the mainstream engine choice, offering good horsepower and value for money. And being an American car, there were quite a few automatics sold.

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These days you read frequently about how a certain car can be had with only an auto or only a manual due to the engine being too powerful or having too much torque. Well, that was not a concept that was heard of back in 1970. Every engine package could be had with a choice of transmission but it was the model and engine size that determined which transmissions were fitted to a particular vehicle. The choices were quite varied and ranged from floor shifters to a column shift, if you were so inclined. Three-speed manual, TorqueFlite automatic and a four-speed manual were the main choices. The strongest was the A-833 4-speed manual as fitted to the big blocks. This gearbox is rough compared to what is available today, but extremely strong. It can be compared to a Toploader gearbox which is a favourite among Ford Falcon GT's. The four speed cars used a Hurst built gear lever known as the "pistol grip" due to the design of the lever which was moulded like the grip of a hand gun and fitted the hand beautifully.

Three different rear axles used to transfer power; these are identified by the diameter of the ring gear. High performance automatics or V8s with manual transmission used an 8.75 inch unit with optional "SureGrip" limited slip gears ranging from 2.76:1 all the way to 3.91:1. Most common were the 3.23 and 3.55:1 gears. Hemi cars fitted with a manual gearbox came with the huge 9.75 inch Dana 60 "SureGrip" axle as standard. Two gear ratios were available: 3.54:1 and 4.10:1. The Dana 60 was an option on the Hemi automatic and 440 engined cars. I mentioned earlier that the Chrysler 4-speed manual was akin to our own Ford Toploader in its ability to take big horsepower. The Dana 60 rear diff surely has to be akin to the famous Ford 9-inch, except stronger.

Racing Heritage

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Throughout the 60's and early 70's the Chrysler muscle cars had been setting records in drag racing. At the head of that campaign was the legendary Hemi engine, which was well respected by competitor manufacturers. The famous "Hemi Under Glass" funny car of Tom McEwen was among the crowd favourites. It was based on a 1965 Plymouth Barracuda with a rear mounted, supercharged and fuel injected, 1000hp Hemi engine that was visible through the rear glass. The factory also released cars such as the Formula S and S\S Hemi Barracuda specifically with racing in mind.

Now that the Barracuda had grown up to the E-body, the Formula S model was gone. Its replacement came about due to Plymouth and Dodge's entry into the SCCA Trans-Am Racing Series. At the time it was considered that if you were not in the SCCA series, you might as well get out of the sports car business. A true 'Race on Sunday, sell on Monday' mentality.

In order to homologate the race cars, a certain number of street versions had to be built. The cars were called the AAR 'Cuda and the Challenger T/A. - in concept like the Ford HO series of the Aussie Falcon GT's.

The styling of these cars screamed with 70's muscle. Both had side exit exhausts, fibreglass hoods with large air scoops, front and rear spoilers, race stripes and decals, and most importantly they were powered by special 340ci blocks, heads and triple carbs (called the Six-Pack). The racing cars used de-stroked versions of the same block and heads but with a single 4bbl carb.

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But it was the big block R/T and 'Cuda models that got the attention of the motoring press though. The 390hp 440ci six-pack and 425hp 426ci Hemi cars could run the quarter mile in the mid 13-second range, which gave them a very powerful reputation on the street.

The End Draws Near

But by now pressure was now being brought to reduce fuel consumption and emissions. Nasty tricks such as exhaust gas recirculation were used to lower emissions but did no favours for the performance of the simple engines. This process started with the 1971 line up, where the 383 received a decrease in compression and the 440 4bbl big block engine was dropped completely. Although the 440 six-pack and 426 Hemi engines remained untouched, this was to be their last year in an E-body.

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The 1972 models were a shadow of the highway-pounding musclecars of just the previous year. The largest engine you could order was the 340ci. No wimp in itself, but when compared to a 426 ci hemi, it was relatively tame. Sales figures were down and the end was in sight for the Chrysler muscle car.

In 1973 the 340 was replaced with the new 360ci engine. A more advanced motor with more cubes was just what the American public wanted, contributing to a temporary boost in sales.

The last Dodge Challenger and Plymouth Barracudas were made in March 1974 as the Arab oil embargo hit the final nail in the coffin.

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