Yenko Chevrolet, located in Canonsburg, Pennsylvania, was one of the largest custom muscle car shops of the late 1960s. The Yenko cars were so popular that, in 1969, Yenko used Chevrolet's Central Office Production Order (COPO) system to have 427 cubic inch engines installed into Chevrolet Novas on the factory assembly lines. The high performance and limited production of all Yenko-customized cars makes them very valuable to collectors.