Duster 340 not a muscle car...
I would say any american made car from 1962-1974 that was V8 single 4BBL or more that had a good power to weight ratio could be a muscle car. If the guy is a Chevy guy he has been brain washed into thinking only a Camaro, Nova, Chevelle are muscle cars and everything else is just a car. He needs a good running 340 to kick his *** that would let him see the error in his thinking. But once a fool always a fool