Running from 1965 to 1970, the fourth generation Chevrolet Impala achieved more than a million US sales in its first year. This was a new record in the automobile industry. The 1965 model was heavily redesigned. The X-shaped frame was replaced with a perimeter frame and new full-coil suspension was included. The four-door hardtop Impala Caprice was introduced as the flagship model in 1965, while another new model, the Custom Coupe, was released in 1968.