One of the minor but contentious arguments among automotive enthusiasts and historians is the question of exactly what constitutes a muscle car. Since we’ll be talking about several cars of this breed in the coming weeks, we thought we’d give you our take on this issue.
The conventional wisdom defines “muscle car” as a performance-oriented American midsize car (usually limited to those built between 1964 and 1973) with a big-displacement engine, inspired by the 1964 Pontiac GTO. Naturally, by the standards of the rest of the world, most American V8s of the period were enormous, but in domestic terms, “big” meant a displacement of at least 370 cubic inches (6 liters, give or take). Similarly, “midsize” was only by comparison with other domestic automobiles, which still meant a wheelbase of 112 to 118 inches (2,845 to 2,997 mm) and an overall length between 190 and 210 inches (4,826 to 5,334 mm).
“Performance-oriented” also demands some qualification. By the late sixties, every U.S. state except Nevada had zealously enforced speed limits of 70 mph (113 km/h) or less, so top speed was not terribly relevant to American drivers. Handling and braking were not high priorities, either, and many of these cars scored poorly in those areas. “Performance,” therefore, meant acceleration, both 0-60 mph (0-97 km/h) and the standing quarter mile (about 400 meters, for our metric readers). The minimum for muscle car status was an elapsed time of less than 16 seconds with trap speeds of more than 90 mph (145 km/h), although some models were naturally much quicker than that.
The trouble with this definition is that there are a lot of potential loopholes. For example, do compacts like the Chevrolet Nova SS count? They had the performance, but they were not midsize cars by the standards of the time. What about a big-engine Ford Mustang or Chevrolet Camaro? Or latter-day cars like the Buick Regal Grand National and GNX (the subject of an upcoming article), which achieved V8-size performance with a turbocharged six-cylinder engine? What about big-block Corvettes?
Our preference is to follow contemporary usage. The term “muscle car” did pop up periodically, most commonly in Road Test magazine (where it was not intended as a compliment), but it was not widely used in the period when these cars were new. The term only really caught on years after most of the original examples were extinct. From the mid-sixties to the mid-seventies, what we now think of as muscle cars were more commonly called “Supercars,” often (though not always) spelled with a capital S.
Contemporary sources applied that term fairly broadly, without the hair-splitting that seems to obsess modern enthusiasts. The term originated to describe the many imitators of the Pontiac GTO, so most of the members of this class were indeed big-engine intermediates. However, the main qualifiers were performance and sharing a body shell with standard passenger cars — the “Clark Kent” models, if you will.
In our observation, contemporary sources had no particular problem classifying a sporty, small-block compact like the Plymouth Duster 340 as a Supercar if it had performance to match. Full-size models like the short-lived Mercury Marauder X-100 were a hazier issue, but would probably have qualified as well. The only reason their status was ambiguous was that by the late sixties, hot full-size cars like the Chevrolet Impala SS had been so eclipsed in sales and performance by their smaller brethren that they were almost irrelevant. They were no longer promoted and rarely even road tested by popular magazines. You could still order an Impala SS427 through 1969, for example, but Chevrolet sold fewer than 2,500 of them that year compared to more than 86,000 mid-size Chevelle SS models.
In this era, the Ford Mustang and its imitators were not generally considered Supercars (except by insurance companies) — not because of their performance, but because they had unique bodies. Mustang-type cars shared many components with more mundane passenger cars, but they had their own body shells. Contemporary sources usually call such cars “sporty cars” or occasionally “pony cars.”
A two-seater like the Chevrolet Corvette (and later, grudgingly, the AMC AMX) was considered neither a Supercar nor a sporty car; it was a sports car. The same went for the early GT-350 Mustang, whose transformation from sporty car to sports car was accomplished by the simple expedient of unbolting and removing the Mustang’s rear seat. European sports car enthusiasts scoffed, but if it was good enough for the Sports Car Club of America (SCCA), it was good enough for most domestic journalists.
In these articles, we generally try to follow the lead of contemporary sources, so we prefer “Supercar” and “sporty car” to “muscle car” and “pony car.” (We’re more likely to use “pony car” than “sporty car” just because it helps to distinguish Mustang-type vehicles from, say, a Dodge Charger or an AMC Rambler Marlin, which did not share the same body shell as their passenger-car cousins, but were clearly in a different size and price class from the Mustang.)
We are hesitant to apply the term Supercar to more modern vehicles, both because the term has come to connote exotic sports cars rather than souped-up passenger cars and because the standards of performance have shifted radically. “Muscle cars” became legendary because for many years, such straight-line performance was quite rarefied. Today, a lot of sixties Supercars could be embarrassed by any number of six-cylinder family sedans, at least in stock form. Furthermore, in a marketing sense, the clearest spiritual heirs to the Supercars are models like the Honda Civic Si and Chevy Cobalt SS, although lumping them in with the vintage GTOs and Road Runners would please fans of neither. We will make occasional exceptions (if you want to call the 2004–2006 Pontiac GTO a Supercar, we certainly aren’t going to argue), but in general, our goal is to put things into their proper historical context, not to make editorial comments about their worth.
Future arguments, like whether a car with a turbocharged V6 can be a muscle car, will be referred back here…
- A Wing and a Prayer: Dodge Charger and Charger Daytona
- Beep Beep: The Irreverent Plymouth Road Runner
- Darth Buick: The Buick Regal Grand National and GNX
- Dodging the Issue: Dodge’s 1966-1967 Fastback Charger
- Fish Story: The Plymouth Barracuda: Part Two: The E-Body Barracuda and Plymouth Duster
- George Hurst and the Hurst Olds
- Going out with a Bang: The 1969 AMC SC/Rambler
- Middle-of-the-Road Muscle: The Oldsmobile Cutlass and 442
- Mean Machine: The 1970-1974 Dodge Challenger
- The Sporting American: The AMC Javelin
- Three Deuces, Four Speeds: The Rise and Fall of the Pontiac GTO
- Wouldn’t You Really Rather: A Brief History of the Buick Gran Sport