Asal mein, if you start tracing the history of the full size Chevys, in the 50s we initially had the Bel Air, which was the first model to really leave its mark amidst the Cadillacs and Pierce Arrows and Dusenbergs of the time. Of course, the '57 Bel Air was one such iconic car. In 1958, the Impala was introduced as the top-of-the-line Bel Air Model. By the year 1965, Chevrolet started a separate line up. The Biscayne was the base model, the Impala was the middle of the range, and the Caprice was the top of the line in terms of trim, and interior fittings etc. Collectively though, all of these were known as Impalas. Later of course, the Impala marquee was phased out altogether, and the Caprice and Caprice Classic took over the mantle as Chevy's premier model, in pretty much the same way as Impala supplanted Bel Air.
Personally - and I say this with the utmost respect to owners of other Chevys - I'm a huge fan of Impalas more than Bel Airs (which came earlier) or Caprices (which came later). To my mind, this model is THE iconic model of all Chevys. The 65 Impala was the vehicle that is attributed to having kick started the very phrase "muscle car"...and Plymouth, Dodge, Pontiac, and other North American manufacturers quickly got onto the idea of bunging enormous engines into two-door full size cars. Which in turn, gave birth to the muscle car craze; a phenomenon which holds to this very day. The sales numbers of a million Impalas sold in 1965, is a record which holds to this day.
More practically speaking, the Biscayne is immediately recognisable by three factors: its inline-six (rather than V8) engine arrangement, and the fact that it has a rear light cluster of four rather than six lights. Finally, and perhaps most importantly, is the logo which reads "Biscayne" rather than "Impala".
History is a fascinating thing, hai na? 
