The 4th Gen Impala continued on with the 1963 and 1964 models. The 1963 Impala got even more angular with chiseled fenders and body lines. While the 1964 Impala continued to use the X frame, the body and grill became less radical with more mature sculpted body lines. Hardtops, convertibles, sedans and station wagons were all steady sales. While base models could be had with a 6 cylinder or a 283 V8, performance models could be had with the 348, or the now popular 409.  One of the more notable variants offered in 1963, was RPO Z11  which provided a stroked 409 to 427ci V8 intended for competitive use. The following year the Fifth Generation Chevrolet Impala was introduced in 1965.