It'll always be a muscle car to me, partially because "pony" carries negative connotations to me (long story), but mainly because I don't get bogged down in that kind of minutiae. If it's American or Australian, it has a V8 available or easily swapped in, and it's not classified as a "light truck", then it's a muscle car - though FWD vehicles (see - Chevrolet Impala and Monte Carlo, which despite the now-discontinued V8 option aren't really muscle cars even in SS form). Of course, there are some exceptions - the Buick Grand National is a muscle car despite using a turbo V6, the Vauxhall VXR8 is a muscle car despite being British (in name only, which is why it counts).