The classification of Muscle Car by many sources, are cars that are overpowered, and go real fast in a straight line, and relatively inexpensive (in it's day). The best examples are like the Super Bee, Challenger, Chevelle, GTX, 'Cuda, and prototypically the GTO. To where the majority of the car is geared toward power, not performance as a Sports or Super Car is. Targeting mostly toward power gives the Muscle Car the relatively squirrely rear-end under heavy acceleration, which we love for drifting purposes.
The 'Vette has always been a well engineered car for performance, not just power. The 'Vette is very fast due to engineering of suspension, lower weight, better aerodynamics, etc. rather than the sheer power alone of a Muscle Car, achieving better performance with less power, thus a sports car.
Not that I think that any of the shots should be removed, as the theme chooser has spoken. But I just wanted to inform to what a Muscle Car was Classically. But then again in the 80's you could get a Mustang in a four-cylinder, which was a popular Muscle Car Nameplate in the 60's-70's, and even with a V6 nowadays, what a shame.