What Is a COPO Camaro?by Mark S. Baker
The COPO Camaro was a Chevrolet muscle car modified by Don Yenko's performance shop. The car was commonly known as a Yenko Super Car or Yenko Super Camaro; (COPO means "Central Office Production Order," a process used to circumvent corporate performance limits). Production Chevrolet engines were limited to 400 cubic inches (6.6 liters) and 396 horsepower (hp). Using the COPO process, vehicles ordered with non-stock options could be made on the production line. The initial modification of these cars ran from 1967 to 1969; additional models were produced in 1981 and a prototype version was introduced in 2009.
How It All Began
In 1967, during the heyday of the muscle car era, Chevrolet introduced the Camaro, its answer to the Ford Mustang. The basic Camaro had an inline-6 powertrain of 230 inches (3.8 liters), which put the top maximum speed at 140 miles per hour (mph). Some came equipped with V-8 engine with a 350-cubic inch (5.7 liters) motor that managed 290 hp. Meanwhile, over at Ford, Mustangs had been being modified by auto designer Carroll Shelby. The 1967 Shelby Mustang, known as the GT500, was being equipped with a 390-cubic-inch (7.0-liter) engine, which was rated at 335 hp. To combat this, Yenko, one of Chevrolet's top-selling dealers at the time, obtained permission from Chevrolet to modify the Camaro.
Modifying the Camaro SS
To get more performance out of the SS 350 Camaro, Yenko swapped out the production engine for an L-72 427 motor that came on a Chevrolet Corvette. These became known as SS 396 L-78 Camaros. In addition to swapping the engine block, the cylinder heads, intake manifold and carburetor were changed to withstand the additional power the engine would generate. As a result, the Yenko Camaro reached a maximum of 425 hp.
Supply and Demand
By 1968, Yenko was having trouble keeping up with modified Camaro requests. Yenko requested to have some Camaros come off the line manufactured with the L-72 427 motor. Using the COPO process, Yenko was to acquire 68 factory 427 Camaros. The Yenko modification for these Camaros included headers, intake manifold, carburetor, wheels, tires, and brakes. In 1969, two versions of the COPO Camaro were produced. The COPO 8561 option came with the regular L-72 427 (made of cast iron) while the COPO 9560 came with an all-aluminum version of the motor -- called the ZL-1 -- so it was much lighter. The Camaros with the ZL-1 motor were rated to have 430 hp, but some tests showed it making closer to 550 hp.
By 1970, interest in muscle cars faded due to higher energy and insurance costs and stricter emission regulations, and no more COPO Camaros were made. In 1981, Chevrolet made a special COPO run of Turbo Z-28 models that were shipped to Yenko, which transformed them into the Yenko Turbo Z. The standard Z-28 Camaro came with a 350-cubic-inch V-8 motor. The primary modifications included the addition of a turbocharger, upgraded wheels and graphics. Some were upgraded with leather seats, stabilizer bars and special shock absorbers. In 2009, a prototype Yenko Camaro was unveiled. As of publication time, no new Yenko Camaros had been produced, although they likely will come with a Z06-sourced LS7 427 6.2-liter V8 engine instead of the standard LS3 376 6.2-liter V8 engine.
Based in Virginia Beach, Mark S. Baker has been working in editorial for more than 20 years. He has served as a writer and editor for publications such as the "Houston Post," "Boca Raton News" and "Interactive Week," among others. Baker also has a culinary arts degree from Johnson & Wales University and has his own catering business.