1967 Pontiac GTO

Purists not tracing the era of muscle cars to the 1949 Oldsmobile Rocket 88 typically mark its beginning with the 1964 GTO. Skirting a General Motors ban against putting big engines -- any engine larger than 330 cubic inches -- into small cars, Pontiac sneaked a 389-cubic-inch V-8 into its Tempest as an option called the GTO in 1964, according to MotorTrend.com. Response was so huge that the car won over GM execs, paving the way for a stable of Chevrolet, Oldsmobile, Buick and Pontiac muscle cars.

Because of its historic value, the 1965 version could represent GTO on this list, but 1967 marked the first full model year of availability of ram air through a functional hood scoop on the GTO. It was a 400-cubic-inch V-8, delivering 360 horsepower.

1970 Chevrolet Chevelle SS 454

Many consider 1970 to be the apex of the muscle-car era, and the Chevelle SS 454 is a weighty piece of evidence for that argument. Chevrolet offered two versions of the 454-cubic-inch V-8. The LS5 generated a very impressive 360 horsepower, while the LS6 punched out a whopping 450 ponies. It's the LS6 version, with its Holley four-barrel carburetor, that put the SS 454 on this list. No other muscle car would equal the horsepower wallop of the 1970 SS 454, according to HowThingsWork.com. It was the last great gasp of the muscle-car era.

Not only could the SS 454 blow the doors off most of its competitors, it looked good doing it. Chevelle's swept-back roof line provided the illusion of speed, even when idle. A bulged hood was part of the design, alerting passers-by that something really special was happening under it.

1969 Ford Mustang Boss 429

The Mustang Boss 429 is what you get when a carmaker needs to meet NASCAR regulations. Fewer than 1,400 were built between 1969 and 1970, making the Boss 429 a rare bird indeed.

Enjoying a big-dog reputation, the Boss 429 wasn't a giant killer right out of the box. Its 429-cubic-inch V-8 engine delivered 375-horsepower, not shabby but dwarfed by others on this list.

What makes it truly notable is that it was basically hand-built. Because the engine wouldn't fit in a standard Mustang without extensive modifications, Ford farmed out its assembly to Michigan-based Kar Kraft. In appearance, very little distinguished the Boss 429 other than a hood scoop and trunk-mounted spoiler.