For 1958, Chevrolet models were redesigned longer, lower, and heavier than their 1957 predecessors, and the Chevrolet Big-Block engine#348 was now an option. The Bel Air gained a halo vehicle in 1958, the Impala, available only as a hardtop coupe and convertible in its introductory year. Impala styling followed the basic lines of the other Chevrolet models but received special styling cues including a different roof line, a vent above the rear window, unique side trim, and triple tail lights housed in slightly broader alcoves. Two significantly cheaper models, the Biscayne (formerly the 210) and the Delray (formerly the 150) were also available during this model year.