At its prime, the Chevelle SS had 450 horsepower and could run the quarter mile in the low 12 second range. Then the gas crisis hit and the muscle car era was over.
We've already covered pony cars in an earlier series, and the line between pony cars and muscle cars is not the clearest one. But even if it is sometimes difficult to see these days, American automakers genuinely did used to try to make a distinction between pony cars and muscle cars. Muscle cars were usually bigger and more expensive, and weren't quite so deliberately aimed at young people.
The distinction is easiest to make when talking about a car made by a manufacturer which also had a pony car in the lineup, and thus the Chevrolet
Chevelle SS is a good starting point. Another big difference between muscle and pony cars is that a pony car is still considered a pony car even in its base trim, whereas muscle cars are usually based on mainstream models and are only considered muscle cars when in performance trim. Thus we have the Chevelle SS, based on one of Chevy's most successful nameplates in history, yet certainly distinct from the station wagons which also wore the Chevelle badge.
The Chevelle was first introduced in 1964, and a Super Sport package was available right from the start. Confusingly, the top trim level of the Chevelle was known as the Malibu, a nameplate which would eventually evolve to replace the Chevelle entirely. The SS package was only available for Malibu models, and SS models would be badged "Malibu SS" for the first couple years of production. The Malibu name would still be applied internally, but the badge on the car disappeared after 1965. This was just one of many changes which happened very rapidly to the SS as the muscle car segment took off like a shot in the mid-sixties.
The original package included some interior and exterior cosmetic touches, a four-speed manual transmission option to replace the three-speed on the base model and a 283-cubic-inch four-barrel engine producing 220 horsepower. In one of the more dramatic examples of automotive evolution, this package, perfectly adequate when it was introduced, was already completely outclassed in just a few months. The package had to be rethought for the Chevelle SS to keep up, even with its corporate cousins, the Pontiac GTO and the Oldsmobile 442. So in mid-1964, a 327cu-in V8 was offered which produced either 250 or 300 horsepower.
The 327-equipped Chevelles could hold their own against the competition, but it was obvious even at the time that the muscle car race would be quickly escalating, and further changes came for 1965. Initially, the big news was the option of a 350 horsepower version of the 327 V8 as the top-level engine for the SS. But toward the end of 1965, a 360 horsepower 396cu-in V8 was also offered. Just 200 (and one prototype) of these big-block first-gen Chevelle SS units were produced and just 75 are known to exist today. But overall, the car was a massive success.
Chevy built 294,160 Chevelles in 1965 alone, and of those 76,860 were SS models. These were huge sales figures at the time, and even though Chevy hadn't yet come out with a direct competitor to the Ford
Mustang, their performance car sales were still strong. It should be mentioned at this point that the El Camino, while often thought of as a separate model, was in fact a body style of the Chevelle, and it was offered with all of the same trims as the standard car. This includes the SS package, and the history of the El Camino SS is essentially the same as that of the Chevelle SS.
That is, the 1964-1977 El Camino was a Chevelle, the '59-'60 models were based on the Brookwood, and '78-'87 models were based on the Malibu, although one could make the case that this was simply an evolution of the Chevelle. It saw a redesign for 1968, and with it, the 327 became available for the standard car and the 396 became the engine for the SS. The SS of this period is often referred to as the SS396, and the engine was tuned to produce between 325 and 375 horsepower depending on packages. The Chevelle was now facing competition from inside, as the higher trim levels of the Camaro (first introduced for in 1967) were pretty firmly inside muscle car territory.
But Chevelle SS sales never faltered, actually increasing to 86,000 in 1969. The big game changer came in 1970, when Chevy started offering the 454cu-in V8. This was available in two states of tune, one producing 360 horsepower and one producing 450 horsepower (at least, that's the official figure, third-party dyno tests have shown it to be about 470 horsepower). These 454-equipped cars could run the quarter mile in the very low twelves completely stock, and represent the pinnacle of Chevelle SS performance. A less-sporty body style debuted in 1973, and SS sales dropped right off, causing Chevy to drop the option at the end of the model year.
The era of the muscle car was ending anyway, and even if sales had kept up, the SS wouldn't have lasted much longer. The Camaro might be the better-remembered car of the era, not to mention the nameplate which has survived, but the muscle car genre would not have been the same without the Chevelle SS.