we have to establish what is a muscle car. I would not say that the mustang 2 or any car after 1974 meets the bill. You could argue about the Trans Am, but as a guide I dont believe in anything after the demise of the E-body mopars. 1972 could really be called the end of the line.
With those criteria in effect, I must say the Buick Riviera with that body style that could not tell its front from its back. Butt ugly!
I guess that "muscle car" was not an appropriate term to use. I think that perhaps the proper thing would be to say any car. My original intent was that the 442 started out as a muscle car but really got watered down until it's worst year 1979.
That being said, I really don't care for the 69 cuda (sorry to Mopar guys), I just didn't care for the fast back...