Does anyone know why most Impalas from '58 to the mid-'70s have three taillights on each side, while the Bel Airs and Biscaynes only had two? I've heard a few lame answers, but no good "story behind the story". ("The Bel Air was a cheaper model, so you paid for the extra taillights in buying the Impala.") I believe when the Caprice was introduced (in '65?) - those had three on each side as well.
...Although it DID make it easier to tell them apart when IDing the cars - heh.
John B.