Muscle Cars

Hot-rodding began before World War II when young men of modest means tinkered with cars to improve their performance. Besides reworking engines, they often lowered the roof or the entire body, to reduce wind resistance. These cars became a symbol of defiant youth, and the basis for more appearance-oriented customizing-gaudy paint jobs and chrome pipes-in the late 1940s and 1950s. Media portrayals of youth culture in the 1950s made icons of these modified vehicles and helped to spread the popularity of customizing.

Opinions on the origin of the muscle car vary, but the 1949 Oldsmobile Rocket 88, created in response to public interest in speed and power, is often cited as the first muscle car. It featured America's first high-compression overhead valve V8 in the smaller, lighter Oldsmobile 76/Chevy body for six-cylinder engines (as opposed to bigger Olds 98 luxury body).

The idea of installing a powerful engine in a post WWII mid-size car was introduced in 1957. The American Motors (AMC) Rebel showcased AMC's new 327 in-³ V8 255 hp with a 4-barrel carburetor (fuel injection was to be optional), thus making it the first American budget-priced and intermediate-sized, factory hot-rod hardtop sedan. The Rambler Rebel came with a manual or automatic transmission, and dual exhaust. The Rebel was promoted as the fastest four-door car in America from 0-€"60 mph (0-€"96.6 km/h) and ran the quarter mile in 17.0 seconds. It was one of the quickest production automobiles at that time.

A muscle car, by the strictest definition, is an intermediate sized, performance oriented model, powered by a large V8 engine, at an affordable price. Most of these models were based on "regular" production vehicles. These vehicles are generally not considered muscle cars, even when equipped with large V8s. If there was a high performance version available, it gets the credit, and not the vehicle that it was based on.

The strict definition only includes intermediate size vehicles. In reality, performance oriented intermediate size vehicles didn't appear until 1964. Before then, manufacturers took existing fullsize vehicles and added extra performance to them. Because of this, the early fullsize performance vehicles are generally considered muscle cars.

In addition to fullsize and intermediate muscle cars, a number of smaller vehicles started appearing on the automotive performance scene. These new "pony cars" and compact cars are generally considered muscle cars only if they have the top of the line performance engines and options.

The year 1970 went down as the peak year for muscle car performance. Beginning in 1971, U.S. automakers began to detune their engines with lower compression, retarded ignition, milder camshafts, and increasingly restrictive intake and exhaust systems in an attempt to meet toughening pollution-control standards. Horsepower ratings began to drop, and would continue to decrease for a generation. Chevrolet lowered the compression ratio of its engines in 1971 to cope with the removal of lead additives from gasoline. Horsepower of its LS6 454 fell from 450 to 425 that year, and would fall much more in coming years.

Part of the decrease in the horsepower ratings manufacturers applied to their engines involved the way in which they measured horsepower output. Prior to 1972, most American automakers rated their engines in terms of SAE (Society of Automotive Engineers) gross horsepower, which was measured using a blueprinted test engine running on a stand without accessories, mufflers, or emissions control devices. This did not provide an accurate measurement of the power output of an installed engine in a street car. Gross horsepower figures were also easily manipulated by carmakers. They could be inflated to make a car appear more muscular or deflated to appease corporate and insurance safety-crats or to qualify a car for a certain class of racing.

By 1972 U.S. carmakers quoted power exclusively in SAE net horsepower, which rated the power of the engine with all accessories and standard intake and exhaust systems installed. This provided a more accurate measurement of a given car's potential, but the overall numbers were lower. Even engines that had received no mechanical changes or additional emissions- control equipment suddenly had lower horsepower ratings in 1972. For example, a 1971 Plymouth 'Cuda equipped with a 340cubic-inch four-barrel was rated at 275 SAE gross horsepower. The same car with no significant mechanical changes was rated at 240 SAE net horsepower in 1972.The 35-horsepower drop was almost entirely due to the different measurement method. To this day, the 1972-1973 versions of the 340-four-barrel engines have reputations as "smog motors," even though they are virtually identical to the 1970-1971 engines.

The psychological effect this had on what was left of the muscle car buying public was a final nail in the coffins of these cars. This was a time before online communities argued ad nauseam about the merits of different brands of valve springs. It was before the Internet, before cable television even, and geniune information was hard to come by. Most hot rodders operated in a fog of misinformation and old wives' tales. People believed the power ratings printed in advertising brochures because often this was the only information available regarding power output. The average buyer didn't know SAE gross from SAE net; he only knew that the horsepower number had suddenly become smaller, and bigger was better than smaller. As a result, some very quick cars built between 1972 and 1974 earned undeserved reputations as underpowered.

As bad as this was, it wasn't the worst thing to happen to the market for high-performance cars. If an aging demographic, Draconian insurance premiums, and increasing encroachment by the federal government weren't enough to kill off muscle cars, the 1973 oil crisis was. This began on October 17, 1973, when Arab members of the Organization of Petroleum Exporting Countries (OPEC) announced that they would no longer ship petroleum to nations that had supported Israel in its conflict with Egypt, which meant the United States and its allies in Western Europe. The effects of the embargo were immediate, and the price of oil quadrupled by 1974. The embargo ended on March 17, 1974, but the aftermath would have a chilling effect on the performance-car market well into the next decade.

By 1973 it seemed to everyone that the muscle car era was dead and gone. Chrysler's Hemi had disappeared, and Chevrolet's 454 was a faint shadow of its former self. When GM management ordered its divisions to drop compression ratios on all their engines, muscle car sales plummeted. GTO sales fell from 40,149 in 1970 to 10,532 in 1971. The year 1972 saw an even more drastic decrease in power output from the big engines along with a corresponding decrease in sales. Discounting the measurement differences created by the change from SAE gross to SAE net, Oldsmobile's 455-cubic-inch engine lost 50 horsepower in 1972. The classic muscle car era appeared to be over. But Pontiac, the brand that had kicked off the muscle car movement in the first place, wasn't about to roll over in submission and urinate on its soft corporate underbelly just yet. In a final act of defiance, the division thrust one last mighty middle finger in the face of the automotive establishment. In 1973, when every other manufacturer had jumped the sinking high- performance ship, Pontiac built something that everyone else thought impossible: a true muscle car.

By this time the last performance car in Pontiac's lineup was the Firebird. The GTO was just a sad option on the restyled LeMans model. The following year it would migrate to the Ventura, Pontiac's version of the lowly Nova, and after that disappear for the next two decades. The sportiest Pontiacs were the Formula and Trans Am Firebirds. The Trans Am package had debuted midway through the 1969 model year, the last year of Pontiac's original Camaro-derived F-car. Even though the name "Trans Am" implies that the car was designed for the SCCA's Trans-American Sedan Racing series, the car was built for the street and never homologated for racing. The name just sounded cool.

In 1970 Pontiac introduced a redesigned Firebird. This redesign allowed Pontiac to build the F-car it had always wanted to build, and the new Firebird quickly earned a reputation for killer handling, especially in Trans Am trim. In addition to sporty bodywork and stripes, the Trans Am package included a number of suspension improvements. The top engine in the 1970 car was a 345-horsepower, 400-cubic-inch Ram Air IV, similar to the top engine offered in that year's GTO.

As with the GTO, Firebird power levels started to drop in 1971. That year Pontiac offered a low-compression version of the 455 HO with an SAE gross horsepower rating of 335 as an optional engine in the Trans Am. Horsepower ratings fell again in 1972, though Pontiac used the better-breathing round-port heads to help compensate for the power drained off by new emissions control equipment. Power appeared to fall yet again in 1973, but that was the case only for those living in the rarified world of numbers on paper. In the real world, 1973 marked a resurgence of Pontiac performance, in the form of the Super Duty 455 option available on the Formula and Trans Am versions of the Firebird.

The SD455 engine combined every high-performance piece remaining in Pontiac parts catalog-radical camshaft, big carburetor, four-bolt main-bearing caps, forged connecting rods, aluminum flat-top pistons-in a last-ditch effort not to let the encroaching nanny state strangle the fun out of performance cars. With a low 8.4:1 compression ratio, the engine was only rated at 290 horsepower, not, seemingly, the stuff of which muscle car legends are made. But that horsepower rating told only part of the Super Duty story.

Consider this: While the SD455 was rated at only 290 horsepower, it was rated at 390 ft-lb of torque, and that was using the SAE net measurement. To put that figure in perspective, while a 426 Hemi had a SAE gross torque rating of 490 ft-lb, when measured using the SAE net method, that same engine generated 390 ft-lb of torque, as did the SD455. Any engine that generates as much torque as a 426 Hemi deserves a place in the pantheon of great motors. Without question the SD455 Firebirds were true muscle cars, as their 13-second quarter-mile times bear out.

They were the last of the true muscle cars, as it turned out. Pontiac got a late start building SD455 Firebirds and only produced 396 examples in 1973. In 1974 Pontiac built 943 SD455 Formulas and Trans Ams before the engine fell victim to the OPEC-induced oil shock. After that, the Super Duty engine disappeared from Pontiac's option list and with it the last of the true big-engine muscle cars. Pontiac would continue trying to maintain its reputation as GM's performance division, producing some admirable cars along the way. Pontiac engineers managed to massage 220 horsepower from the 400-cubic-inch engine used in the 1978 Trans Am, and even resorted to turbo charging when it was forced to scale back to a small 301-cubic-inch engine for the 1980 Trans Am. But they were fighting a losing battle. It would be nearly two decades before performance once again rose to SD455 levels.

Following the demise of the SD455, the performance car market in the United States entered its Dark Ages. After offering a series of huge-displacement engines that generated embarrassingly small amounts of horsepower-imagine a 455-cubic-inch engine that produced just 160 ponies-the big motors disappeared. Various manufacturers attempted to stir interest in the youth market by putting legendary nameplates like "Road Runner," "4-4-2," and "Cobra" on lowly econocars and pimped-out personal luxury cars, but no one cared anymore.

Oldsmobile had a few good years in the late 1970s. With their crushed-velour interiors and vinyl landau tops, Oldsmobile built the right car for the times. The late 1960s had been defined by excessive automobile abuse; the late 1970s were defined by excessive self-abuse. Oldsmobile's Cutlass, the best-selling intermediate-sized car of the era, with its brothel-on-wheels persona, provided an ideal atmosphere in which to snort cocaine, the drug of choice at the time.

Pontiac generated some excitement with its 400-cubic-inch Trans Am in 1978, but the 220-horsepower car was just a faint echo of the SD455 version offered a few years earlier. Still, it was a damned sight better than the dreadful cars offered by Pontiac's competitors.

Although shortlived, muscle cars have become famous the world over from countless films like Vanishing Point and Bullitt and for their amazing performance, at least in a straight line. The muscle car era lasted just eight years between 1964 and 1972 but it ushered in a horsepower war which saw humble Chevrolets producing upwards of 450bhp from a 7.4-litre V8. As Americans say, "there ain't no substitute for cubic inches".

Todd Lassa. Muscle Cars Comparison: 1970 AMC Rebel Machine, 1970 Mercury Cyclone Spoiler GT, 1970 Plymouth GTX, and 1970 Buick GSX Stage I. Motor Trend Magazine . Paul Zararine. Brute Force. Musclecar Enthusiast. November 2007.

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