In 1958, Chevrolet renamed the base series from One-Fifty to Delray. The mid level series was renamed from Two-Ten to Biscayne and Bel Air remained the top of the line series. The Impala was part of the Bel Air line. Chevrolet also used numeric codes for the three series. 1100 & 1200 (6 & V8) were the base model numeric IDs, 1500 & 1600 were the mid level series and 1700 & 1800 were the top of the line series. For 1958 all Bel Air models started with either 1700 (six cylinder) or 1800 (V8). 1747 is a six cylinder Bel Air Impala sport coupe and 1847 is a V8 Bel Air Impala sport coupe. 1767 is a six cylinder Bel Air Impala convertible and 1867 is a V8 Bel Air Impala convertible. The Impala would become the top of the line series in 1959, dropping the Bel Air to mid level status and the Biscayne to entry level (base) status. The Delray name was dropped altogether.