Muscle Car History
Article by Mark Trotta
Although muscle car sales were relatively modest by Detroit production standards, they hold a huge place in classic car history. Sold at an affordable price, they were intended for street use and occasional drag racing. Although the origins of the first muscle car are often debated, there is no question that they ruled American streets from 1964 through 1970 (and a little beyond).
In the early 1960's, few people were concerned with gas prices when premium was 35 cents-a-gallon. Cheap gas and cheap horsepower was the order of the day.
In 1964, there were Oldsmobile, Chevrolet, and Pontiac muscle cars, with Buick joining in a year later. Ford offered the Fairlane 500 and later the 428 CobraJet. Chrysler unveiled the 426 street Hemi engine in 1966, seen in the Dodge Charger, then later in the Plymouth GTX and Road Runner.
By 1970, every U.S. car manufacturer offered a factory hot rod with youth-oriented advertising. Even safety-conscious American Motors Corporation joined in, offering the SC/Rambler and Rebel Machine.
American Youth Market
Muscle car history starts with Baby Boomers coming of (drivers) age and America's love for speed and competition. The popularity of pony cars and muscle cars grew while Dodge, Plymouth, GM, and Ford all battled for supremacy at drag strips across America.
In the early sixties, General Motors had a corporate policy which stated that intermediate-cars could not have engines larger than 330 cubic inches, but this policy did not seem to apply on options. Pontiac got around the rules by advertising a 389ci-equipped Tempest as a special-option model.
The GTO project, spearheaded by Pontiac division president John DeLorean, technically violated GM's policy, but proved to be much more popular than expected. The sales success of the 389ci Tempest GTO prompted other car companies to use the same formula, and soon there were numerous imitators.
Read: Pontiac GTO History
History clearly shows that Pontiac wasn't the first car company to drop a big motor in a mid-sized car, but they were the first to market a mid-sized car with a big motor. Rivaling anything on the road in straight-line acceleration, the Tempest-based 1964 GTO was wildly successful. In 1969, Pontiac's GTO Judge featured wild graphics and a standard 400ci V8.
Sharing the B-body platform with the Coronet (Dodge's intermediate-sized car in 1965), the Charger's long body rode on a 117-inch wheelbase. Front sheet metal resembled the Coronet slightly, but the Charger's grille was wider, smoother, and featured fully rotating, electrically-operated retractable headlights. Helping the 3,600 pound car look sporty was the wide fastback which stretched all the way to the rear bumper. Chrome block letters spaced across the tail-lights spelled "CHARGER".
Read: Dodge Charger History
The 1966 Dodge Charger's base transmission was a column-shifted three speed manual, with a four-on-the-floor manual or three-speed automatic optional. With nothing but V-8's under the hood, a two-barrel, 230 horsepower 318ci engine was standard. Optional was a 265-horsepower 361 motor, a 325-horsepower 383 engine, and a street version of Chrysler's 426 Hemi race engine.
Introduced as the Belvedere GTX in 1967, the Plymouth GTX was offered in both hardtop and convertible body styles, with 1969 being the last year for the latter. Also that year, the GTX received minor cosmetic changes, along with an optional Air Grabber hood (standard with Hemi-powered models). The standard "Super Commando" 440 V8 was rated at 375 horsepower, and the optional 426 engine produced over 425 horsepower. A stock GTX 440 with automatic transmission and 3.23 rear gears could run the quarter-mile in 14.4 seconds at 98 mph.
First Street Hemi
When the 426 Hemi was first seen in 1964, it was strictly a racing engine. After Hemi-powered Mopars dominated the that year's Daytona 500 (finishing 1-2-3-4) they were quickly banned unless the motors were offered to the general public. This meant installing them in "ordinary" production vehicles. Huge by any standards, the 426 Street Hemi was nicknamed "Elephant Engine" not only for its cubic capacity and power, but for its 800-plus pound weight. The first street Hemi appeared in 1966 B-body Dodges and Plymouths, including the first-year Dodge Charger.
With a 4.25 inch bore and 3.75 stroke, the seven-litre Hemi V-8 was based on an iron block with four-bolt-main, cross-bolted caps. The crankshaft was forged-steel, as were the connecting rods. For induction, the street Hemi had an aluminum dual-plane, dual-carb manifold with two Carter AFB four-barrel carburetors mounted in-line. With a solid-lifter camshaft, 425 horsepower was advertised, but actual output was closer to 500. Torque was listed at 490 lb/ft at 4000 rpm. Compression ratio for the street Hemi was 10.25:1.
Plymouth Road Runner
Due to increases in optional equipment and luxury appointments, muscle cars were becoming more expensive. In response to rising cost and weight, a secondary trend towards more basic "budget" muscle cars emerged in 1967 and 1968.
Although Plymouth's bare-bones muscle car had a plain vinyl bench seat and few options available, everything essential to performance was there, including the standard "Road Runner 383" V8 rated at 335 horsepower and 425 lb/ft of torque. Optional was the 426ci Hemi, rated at 425 horsepower and 490 lb/ft of torque. The standard transmission was a 4-speed manual with floor shifter. Chrysler's three-speed TorqueFlite automatic was optional.
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Plymouth expected to sell about 20,000 Road Runners in 1968. Actual sales numbered around 45,000. This placed the Road Runner third in sales behind the Pontiac GTO and the Chevelle SS396. Equipped with high-performance carburetor, exhaust manifolds, and slick tires, a 383ci Road Runner could run a 14.7 quarter-mile at 100.6 mph.
The name "4-4-2" (pronounced "four-four-two") stands for four-barrel carburetor, four-speed manual transmission, and dual exhausts. Like the Chevelle and GTO, the 442 was an optional trim level package on lower models (Olds Cutlass and F-85) for the 1964 model year. In 1965, engine size grew from 330ci to 400ci. The 442 became a model in it's own right in 1968.
After Chevrolet introduced their small-block V8 in 1955, they were virtually unchallenged on the street. That was until 1964, when the 389ci GTO appeared. The 1964 Chevelle was offered with either a 283ci or 327ci small-block engine. After Oldsmobile offered a 400-cid 442 and Buick a 401ci Gran Sport in early 1965, that was all it took for Chevy to break GM's policy for A-body series engines. A new big-block V8, at 396 cubic-inches, was scheduled for release in full-size Chevys and Corvettes. It would also be the standard engine in the Chevelle Super Sport package.
Buick Gran Sport
Also based off the GM A-body platform was the Buick Gran Sport. Although a 300ci V8 was already offered in the Skylark, the Gran Sport came with the largest engine permitted by GM at the time, a 400ci V8. The engine was actually 401ci, but called a 400 because that was the maximum engine size allowed. The engine produced 325 horsepower and 445 lb/ft.
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In 1967, a 340ci version was added, sold as the GS 340 and the GS California sub-model. The following year, it was replaced with the GS 350. For 1968 and 1969, Buick offered a GS 400 in both convertible and hardtop model.
Ford Torino GT
After the successful 390ci Fairlane GT and GTA (and Comet Cyclone), Ford followed up with the introduction of the Torino in 1968. The Torino was initially an upscale version of the Fairlane, with the most popular-selling models being the 4-door sedans and 2-door hardtops. The Torino GT came standard with a 302ci V-8 engine, bucket seats, console, tachometer, and power front-disc brakes. An available 335-horsepower 428ci CobraJet V-8 propelled the Torino into muscle car history.
Based on the Torino GT, the CobraJet featured special red and chrome 428 badging to set them apart from the standard Torino GT. Three-speed and four-speed manual transmissions and a three-speed automatic were available. Also available was a suspension package with heavy-duty shocks and a front stabilizer bar. A 1969 Fairlane Cobra 428 with an automatic would run 13.50- 14.0 ETs at 100+ mph.
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The Cobra came standard with the 428 CobraJet motor, 4-speed manual transmission, heavy-duty suspension, and F-70x14 tires mounted on six-inch wheels. Options included a functional Ram-Air hood scoop, and a "Traction-Lok" limited-slip differential with choices of gearing. Exterior features included a blacked-out grille, hood lock pins, and Cobra emblems.
American Motors gained credibility with muscle car fans in 1967, when it made both the Marlin and the Rebel available with a 280 horsepower, 340ci V8. A year later, the Javelin and the two-seat AMX debuted. In 1969, the 390 SC/Rambler was offered.
AMC Rebel Machine
Based on the mid-size Rebel platform, AMC's Rebel Machine came standard with a 390ci V8 producing 340 horsepower and 430 lb-ft. Compression ratio was 10.0:1. A large ram-air intake hood scoop that was painted Electric Blue (code B6) with a large tachometer visible to the driver integrated into a raised fairing at the rear of the scoop. A 4-speed transmission with Hurst shifter was also standard, along with a 3.54:1 rear gear ratio.
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Offered in 1970 only, the 3,800-pound AMC Machine ran the quarter-mile in 14.57 seconds at 92.77 mph. Although most were ordered with the red, white, and blue paint scheme, the Rebel Machines' were also available in solid "everyday" colors.
1970 - Pinnacle of the Muscle Car Era
Competition between manufacturers gave buyers ever-more powerful engines. Horsepower ratings peaked in 1970, with some models offering as much as 450 horsepower. In order to keep up with other manufacturers, General Motors dropped the limit on engine size.
In 1970, Oldsmobile made their huge 455ci V8 the standard 4-4-2 plant. When equipped with the potent W-30 package, the engine produced 360 horsepower and 500 lb/ft of torque. With a 4-speed manual transmission and 3.91:1 rear gears, the 4-4-2 ran the quarter mile in 13.7 seconds.
Based on the Buick Skylark, the Buick GSX was introduced in 1970, five years after the Gran Sport hit the market. The 455ci engine was fitted with improved heads, larger valves and a hotter camshaft. The motor was rated as high as 360 horsepower with 510 foot-pounds of torque, and the 3,810 pound GSX was available in yellow or white only with racing stripes. The relatively unknown, and very expensive GS 455 Stage 1 ran a 13.38 ET at 105.5 MPH.
In 1970, the Chevy big-block's displacement was increased to 454ci and offered in either 345 or 390 advertised horsepower versions. The higher output LS6 featured a single Holley 780-CFM 4-bbl carb and 11.25:1 compression ratio.
In the quarter mile, a stock 1970 LS6 Chevelle with automatic transmission and 3.70 rear gears could run a 13.81 ET at 103.8 mph. A conservative estimate of the LS6's power puts it at 450 horsepower and 500 lb/ft of torque.
Dodge Charger Daytona
Offered as an option package, the Dodge Charger Daytona was introduced on April 13, 1969. From it's wedge-shaped nose to the 23-inch rear wing, the 1969 Daytona Charger measured 18-feet long and was capable of speeds no other production car could match. Standard equipment included heavy-duty suspension and brakes, and the Torqueflite three-speed automatic transmission. A four-speed manual was optional.
Read: Dodge Charger Daytona
Base motor for the Charger Daytona was the 440 cubic-inch Magnum V8, producing 375-horsepower at 4,600 rpm, with 480 lb-ft of torque at 3200 rpm. The optional 426 Hemi motor was rated at 425-horsepower at 5,000 rpm and had 490 lb-ft of torque at 4000 rpm. Plymouth applied the Daytona formula to their Road Runner in 1970, creating the Superbird.
Decline of the Muscle Car
The power of muscle cars underlined their marginal brakes, handling, and tire adhesion. In response, the automobile insurance industry added surcharges on all high-performance models, an added cost that put many muscle cars out of reach of their intended buyers.
A majority of muscle cars came optioned with high-compression engines, some as high as 11.25:1. 100-octane fuel was common until the passage of the Clean Air Act of 1970, where octane ratings were lowered to 91. This was due in part of the removal of tetraethyl lead as a valve lubricant. Unleaded gasoline began to be phased in.
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Starting in 1971, engine compressions were reduced to run on unleaded gas, and engineers were struggling to satisfy emissions and safety regulations. Horsepower ratings began to drop, and high-performance engines like the Chrysler 426 Hemi were discontinued.
Prior to 1972, published horsepower ratings were expressed as SAE (Society of Automotive Engineers) Gross. These figures reflected an engine's output without power-robbing accessories, such as cooling fan, exhaust system, and alternator. Starting in 1971 and going industry-wide in 1972, engine output was expressed as SAE Net, with horsepower measured at the rear wheel. The result was lower advertised horsepower ratings.
U.S. Oil Embargo
On October 16, 1973, in response to American aid to Israel, the Organization of the Petroleum Exporting Countries (OPEC) raised the posted price of oil by 70%. This oil embargo led to price controls and gasoline rationing, and strained a U.S. economy that had grown increasingly dependent on foreign oil. The 1973 U.S. Oil Crisis made the gas-thirsty muscle cars fall even further in the marketplace.
Around 1974, muscle cars began to shrink in both stature and performance. All but a handful of performance models were discontinued or transformed into lower horsepower personal luxury cars. Nameplates like Chevy SS and Olds 442 would become sport appearance packages. With all these forces against it, the market for muscle cars quickly faded.
By 1979, the only remaining cars with any muscle were the Pontiac Firebird Trans-Am and Chevroletís Camaro Z28 and Corvette. Pontiac sold 117,109 Trans-Ams that year. Chevrolet sold 84,877 Z-28s and 53,807 Corvettes.
The Muscle Car era was short-lived, but gave us some of the most memorable cars in automotive history. Today, some of the most highly sought classic cars are original muscle cars from 1964-1974.