Its reliability and easy maintenance made the Opala the choice of many taxi drivers and was also popular on racetracks.

[6] The Opala "Coupé" continued as a pillarless hardtop well into the late 1980s, long after U.S. automakers dropped the body style.

The Opala's long-lived 250-cubic-inch (4.1 L) engine was also used in its replacement, the Chevrolet Omega (which featured electronic fuel injection in the GLS and CD trims) from 1995 to 1998.

Founded in January 1925, General Motors do Brasil originally only assembled, and later, manufactured, light trucks and utilities until the late-1960s, when they decided to produce their first Brazilian-made passenger car.

The options varied between the traditional, large, more expensive American-style cars that GM was already selling in the United States line, such as the Impala, and the lighter and more economical models from German GM-subsidiary Opel (such as the Kadett, Olympia, Rekord and Commodore) which were already imported to Brazil in small quantities.

On November 23, 1966, in a press conference at the Club Athletico Paulistano in São Paulo, GM publicly announced "Project 676", which would become the Chevrolet Opala.

[7] The name Opala may come from the opal, which is a precious stone, colourless when extracted from the soil, but which acquires multiple tones when exposed to light.

At the opening of the sixth São Paulo Auto Show, on November 23, 1968, the Opala appeared on a rotating stage on a 16,140 square feet (1,499 m2) stand.

Reverse lights, fuel tank lock, and rear valance chrome strip were available only on the "Luxo" trim level.

In the fall of 1970, a better equipped version called Comodoro was added, the name reflecting Europe's Opel Commodore.

The straight-six's biggest limitation through the years was poor distribution of air-fuel mixture to the cylinders due to a sub-optimal intake manifold design.

Basically, in order to ensure the outer cylinders received a high enough air/fuel ratio to avoid detonation, the carburetor had to be set to run overly rich, which wasted fuel).

It took Bob Sharp and Jan Balder, who placed second in the "24 Hours of Interlagos" in August of that year with an Opala, to convince GM do Brasil to field a more powerful engine.

It was slightly different from the version that would be launched two years later: it didn't have a vibration dampener and the cooling fan came from the standard 2500, with four blades instead of six.