So what IS a muscle car?

I was talking to a guy this weekend about his corvette. He said when he bought in the 70s he was hauling *** down the highway in the middle of the night and his buddy said there’s a car catching up to us. He said it’s either a COP or a Mopar. Sure enough he said it was a Mopar, a Coronet Wagon loaded down. Passed him up like he was sitting still. The old man driving just waved as he passed him at over 100mph