Chevrolet 153 4-cylinder engine

The compact Chevrolet Corvair was introduced in 1960 to compete with the Ford Falcon and Plymouth Valiant, but was handily outsold by its competitors. Fearing the Corvair's more radical engineering (featuring a rear-mounted air-cooled flat-six engine) was not appealing to consumers GM hastily approved the design of a new, more conventional compact car to compete with the Falcon and Valiant. Within 18 months the design of the Chevy II was completed, including new 153 cu in (2,512 cc) four-cylinder and 194 cu in (3,185 cc) six-cylinder engines to power it.

The 153 cu in engine had a 3 ⁷⁄₈-inch (98 mm) bore and 3 ¹⁄₄-inch (82.6 mm) stroke, with two overhead valves per cylinder actuated by pushrods and a 1-3-4-2 firing order. The Chevy II's 194 cu in six-cylinder used a 3 ⁹⁄₁₆-inch (90.5 mm) bore, which by 1964 was enlarged to match the 153 four-cylinder's resulting in a displacement of 230 cu in (3,768 cc). The 230 cu in six and 153 cu in four are thus essentially the same design, differing only in cylinder count.

The 153 engine was used by GM do Brasil in their first locally-made product, the 1968 Chevrolet Opala. In 1973 the Brazilian engineers redesigned the engine in order to quell vibrations, decreasing the stroke to 3 inches (76 mm) and increasing the connecting rod lengths to 6 inches (150 mm).[1] To keep the power output similar to the 153 they correspondingly increased the bore to 4 inches (100 mm), resulting in 151 cu in (2,471 cc) displacement. This 2,471 cc variant of the engine was in production in the Opala until 1992. Coincidentally the bore and stroke are the exact same as the Pontiac Iron Duke engine introduced in North America in 1977, but the two engines are otherwise unrelated and do not share parts.[1] As is customary in Brazil the engine was refit to accept ethanol fuel.

This engine was a mainstay for GMSA, who built it in their Aloes Plant (on the northern edge of Port Elizabeth) for installation in a wide range of cars. Two smaller displacement versions of this engine were also built there: a 2,319 cc (141.5 cu in) variant using the 153's bore and the Brazilian 151 cu in engine's 3-inch (76.2 mm) stroke,[2] and a 1,960 cc (119.6 cu in) variant which used the 153's stroke and the 194 cu in six-cylinder's 3 ⁹⁄₁₆-inch (90.5 mm) bore.[3] The engine was also used by the SADF in the Eland armoured car from the Mk. 5 upgrade.

• 1962–1970 Chevrolet Chevy II / Nova
• 1964 Chevrolet Van
• 1968–1970 Jeep DJ-5A
• 1968–1991 Chevrolet Opala (Brazil)
• 1971-1975 Chevrolet Firenza (2.5, South Africa)
• 197?-1978 Chevrolet 2500 (2.5, South Africa)
• 1975-1978 Chevrolet 1900 (2.0, South Africa)
• 1976-1982 Chevrolet Chevair (2.0 and 2.3, South Africa)[2][3]
• 1978-1982 Chevrolet Rekord (2.3, South Africa)[2]

GM produced a variant of the 153 for use in industrial and marine applications, with the Brazilian version's larger 4-inch (101.6 mm) bore and a longer 3.6-inch (91.4 mm) stroke. The resulting 3.0 L (181 cu in) engine, branded the Vortec 3000, was never installed in passenger cars. The Vortec 3000 is manufactured in Mexico where 1992-to-present engines have a one-piece rear seal similar to the one used with the Chevrolet small-block and 90-degree V6 (the flywheel bolt pattern for the later-production 3-liter does not interchange with the earlier 153 or 181 which uses the small-block and inline-six's 3.58-inch bolt-circle, and does not use the 1986-present one-piece rear-seal flywheels since the bolt pattern is larger).

Later variants of the Vortec 3000 had modified cylinder heads where machined bosses were drilled for use with multipoint fuel injection.