I'll bring the statistics of the Muscle Cars later.

New Age of classic? The new age muscle cars are only the Mustang, Challenger, Charger and Camaro. And the fastest is the Mustang GT500. Out of the old muscle cars, I think it's either the Camaro Z28, Firebird Trans Am or Mustang Boss 302.

http://www.musclecarclub.com/musclecars/general/musclecars-50fast.shtml

Basically, the fastest muscle car is the Plymouth Road Runner with the 440, as the Cobra and Corvette, although similairly powered by really big V8s, are basically sports cars.

As for the three you listed, Conor, they're technically pony cars, although they usually get lumped in anyways though. But the Boss 302 is unquestionably not the fastest Mustang, and the Z-28 isn't the fastest Camaro. I'm sure you're familiar with the phrase, "no replacement for displacement," and of course, the Boss 302 and the Z28 were built as road going counterparts to Trans Am cars, which had a 305c.i. limit on engines. Ironically, the Trans Am started off using big block engines that wouldn't be legal in the series.