As the drag racing wars continued to escalate, so did the efforts to find ways to win. Lighter cars and bigger engines were one quick means to an end. For Chevrolet, one of their attempts was the Impala Z11 with a modified 409 engine. In 1963 and 1964, the Impala was could be fitted with various types of engines with results ranging from 340 to 425 horsepower. The Z-11 was devoid of heaters, radios, sound deadening insulation, and any other non-essential items. In total, there were only 47 examples produced and even fewer exist in modern time.