The L72 was a 90°

overhead valve An overhead valve (OHV) engine, sometimes called a ''pushrod engine'', is a piston engine whose valves are located in the cylinder head above the combustion chamber. This contrasts with earlier flathead engines, where the valves were located be ...

big-block A V8 engine is an eight-cylinder piston engine in which two banks of four cylinders share a common crankshaft and are arranged in a V configuration. The first V8 engine was produced by the French Antoinette company in 1904, developed and use ...

engine produced by Chevrolet between 1966 and 1969. Initially rated at 450 horsepower, the rating dropped to shortly after its release (although there was no change in power). In 1966 it was the most powerful engine available in the

Corvette A corvette is a small warship. It is traditionally the smallest class of vessel considered to be a proper (or " rated") warship. The warship class above the corvette is that of the frigate, while the class below was historically that of the slo ...

, and between 1966 and 1969 was the most powerful engine available in full-sized models. In 1969 the L72 was available via a Central Office Production Order (COPO) in Chevrolet's intermediate ( Chevelle) and pony car (

Camaro The Chevrolet Camaro is a mid-size American automobile manufactured by Chevrolet, classified as a pony car. It first went on sale on September 29, 1966, for the 1967 model year and was designed to compete with the Ford Mustang. The Camaro share ...

). Today these vehicles - referred to as COPOs - are among the most collectible 1960s performance cars.

History

Chevrolet's second generation big-block, the Mark IV had been introduced in 1965 in two versions. In 1966 Chevrolet added a version that was available exclusively in the sports car (Corvette) and full-sized (

Impala The impala or rooibok (''Aepyceros melampus'') is a medium-sized antelope found in eastern and southern Africa. The only extant member of the genus '' Aepyceros'' and tribe Aepycerotini, it was first described to European audiences by Germa ...

, Bel Air, Biscayne) lines. While a 396 was still available in full-sized cars, the L72 and the lower performance L36 became the only big-block options in the Corvette. Although 11 known L72 engines were known to be built for installation into passenger cars for 1967, no known cars got this engine from the factory. One 1967 Impala SS427 was reported to have been built with the L72, however that car has been confirmed to have been modified after its sale to a customer and is not an authentic L72 factory car. Starting in 1968, the L72 once more became a factory option for the big Chevys. In 1969, through a Central Office Production Order, one could order an intermediate ( Chevelle) or

pony car Pony car is an American car classification for affordable, compact, highly styled coupés or convertibles with a "sporty" or performance-oriented image. Common characteristics include rear-wheel drive, a long hood, a short decklid, a wide range ...

(

) with an L72. The COPO option bypassed an internal rule that disallowed engines above on cars other than the full sized or Corvette. Today these COPO cars are among the most collectible Chevrolets. The L72 is also noted for its use in cars built by

Don Yenko Donald "Don" Frank Yenko (May 27, 1927March 5, 1987) was an American car dealer and racecar driver best known for creating the Yenko Camaro, a high-performance version of the Chevrolet Camaro. Biography Early life Yenko grew up in Bentleyville, P ...

. Yenko equipped Camaros with L72s from 1967 to 1969, and equipped Chevelles and Novas in 1969. The 1969 Camaros and Chevelles were ordered with COPO L72s, while all others were conversions.

L71

In 1967 Chevrolet introduced the L71, a variant of the L72. This new engine had three 2-barrel

carburetor A carburetor (also spelled carburettor) is a device used by an internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the venturi tube in the main meteri ...

s - known as "

tri power * Tri- is a numerical prefix meaning 3, three. Tri or TRI may also refer to: Places * Tri-Cities Regional Airport, Tennessee, US, IATA code TRI * Triangulum constellation, astronomical abbreviation Tri People *Tri, Former nickname for wrestler T ...

" - in lieu of the single 4-barrel of the L72, and a rating. Aside from the intake setup, the two engines were identical. As of 1967 the L72 was no longer available in the Corvette, making it exclusive to the full-sized line. The L89 option could also be ordered with the L71, replacing the cast iron cylinder heads for aluminum versions. This option did not change performance, but reduced weight by roughly .

Production numbers

* * The L72 was not advertised in any 1967 sales literature. * ** 99 of these were converted into Yenko Super Cars. * *** 198 of these were converted into Yenko Super Cars.

References

{{Reflist *DeMauro, Thomas A. "Buyer's Guide: 1966 L72 427/425hp Chevrolet Biscayne." In ''Hemmings Muscle Machines.'' August 2013. *Shea, Terry. "One of ...? - 1967 Chevrolet Impala SS 427." In ''Hemmings Muscle Machines.'' September 2012. Chevrolet engines V8 engines Gasoline engines by model