Muscle cars are the epitome of American mechanical engineering. For a price not much more than an economy sedan, one could have himself a 300+ horsepower monster that could beat cars twice as expensive in a straight-line race. Their large displacement engines (sometimes more than 400 cubic inches!) produced enough low-end torque to send the front end of the car airborne. Every bit of possible torque was squeezed out of these engines with ingenious modifications, such as 13:1 compression ratios and huge superchargers popping out of hoods. The peak of the muscle car era was in the 60's, with the Pontiac GTO's, the Chevelle SS's, and other fine American offerings. In the mid 60's, the pony car line was introduced, whose three top members were the Mustang, Camaro, and Firebird. Although the latter two cars were nearly as powerful as the muscle cars, most people would not put a Mustang in the same class as a muscle car.
Unfortunately, the radical left wing takes it toll on all things American, and the muscle car era was no exception. After the Clean Air Act was introduced in America, there would be no more high octane leaded gasoline, no more gas-guzzling big blocks, no more muscle car. Although the Camaros and Firebirds lived on, they are "marked for destruction" and will no longer be produced, leaving only the Ford Mustang, an underpowered pony car that is undeserving of the muscle car designation.