Owners could achieve fuel economy of around 13 city and 20 highway. The firing order of the 4.1L straight-six is 1-5-3-6-2-4. The 250 has a bore of 3.875 inches (98.425mm) and a stroke of 3.53 inches (89.662mm).ĮNGINECHEVY 250 INLINE-SIXMANUFACTURERGENERAL MOTORSYEARS PRODUCED1966 to 1984DISPLACEMENT250CI (4.1L)CONFIGURATIONINLINE SIX FUEL TYPEGASOLINECOMPRESSION RATIO8.5:1FIRING ORDER1-5-3-6-2-4BORE3.875 INCHES (98.425 MM)STROKE3.53 INCHES (89.662 MM)HORSEPOWER (1970)155 HP (115.58 kW)TORQUE235 LB-FTGAS MILEAGE13-22 MPG (EST) The 250 was a stroked version of the smaller 3rd generation GM six-cylinder engines. It originally produced 155 horsepower and 235 lb-ft of torque with a one-barrel Rochester Monojet carburetor.

The Chevy 250 straight-6 engine was a single-cam overhead-valve inline-six. Interestingly, GM continued manufacturing the third generation inline-six in Brazil until 2001. Base-model vehicles once equipped with the 250 switched over to the 4.3-liter V6. Chevrolet discontinued the 250 in 1979 for passenger cars and 1984-5 for trucks. Other engines in the series include the 3.2-liter 194 and the 3.8-liter 230 (not to be confused with the later GM 3.8-liter V6). Contrary to popular belief, the 250 was not the largest of the third-gen Chevy sixes that title goes to the Chevy 292 engine. The 250 itself became available in the lineup in 1966 due to the demand for a larger motor on the familiar platform. The Chevy 250 is part of the General Motors third-gen inline-six platform, which was introduced in 1962.

Gm inline 6 casting numbers 877127