Building an inline 6 Chevy 250 engine
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(→Intake manifolds) |
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Throughout its production lifecycle, the inline 6 Chevrolet came with a one barrel carburetor. Carter YF carburetors were used with the early engines until some point in the mid-1960s when the Rochester Monojet (1MV) was phased into production. The 1MV was used until the end of the 1979 model year (with passenger cars) but continued production with the 292 until its 1990 phaseout in North America and marine applications. Rochester 2SE (Varajet) was introduced in 1978 - only known vehicles using the Varajet were the C/K light duty truck (half ton) and G-series vans including the P series box vans. One drawback is the uneven fuel mixture with the stock one barrel carburetor where the front and rear cylinders have an uneven fuel distribution. | Throughout its production lifecycle, the inline 6 Chevrolet came with a one barrel carburetor. Carter YF carburetors were used with the early engines until some point in the mid-1960s when the Rochester Monojet (1MV) was phased into production. The 1MV was used until the end of the 1979 model year (with passenger cars) but continued production with the 292 until its 1990 phaseout in North America and marine applications. Rochester 2SE (Varajet) was introduced in 1978 - only known vehicles using the Varajet were the C/K light duty truck (half ton) and G-series vans including the P series box vans. One drawback is the uneven fuel mixture with the stock one barrel carburetor where the front and rear cylinders have an uneven fuel distribution. | ||
| − | Beginning in the mid-'70s, the inline 6 Chevy (with the exception of the tall deck 292) got an integrated intake cylinder head similar in design to the Ford Falcon Six. This was a step in the wrong direction for a performance engine- the intake being cast as part of the head means it would take too much work to remove it to be able to use any kind of 4-barrel carb. There are three different designs for the integrated head - casting number #355795, #370696 was used with the mass market passenger cars e.g. X and F platform automobiles (Nova (includes its rebadged clones), Camaro) which has a wide footprint valve cover. A mid-cycle refresh in 1977 with casting number 377131 with the one barrel carburetor base continued in production until 1979 but used a valve cover sized similarly to the conventional head with a shorter height, smooth face, and the PCV tube behind the oil fill hole. Light duty trucks c. 1978 - 1984 will have casting 14015499 (this one has the Varajet carburetor base - integrated intake runners are curved and incorporate a dual outlet exhaust manifold). | + | Beginning in the mid-'70s, the inline 6 Chevy (with the exception of the tall deck 292) got an integrated intake cylinder head similar in design to the Ford Falcon Six. This was a step in the wrong direction for a performance engine- the intake being cast as part of the head means it would take too much work to remove it to be able to use any kind of 4-barrel carb. There are three different designs for the integrated head - casting number #355795, #370696 was used with the mass market passenger cars e.g. X and F platform automobiles (Nova (includes its rebadged clones), Camaro) which has a wide footprint valve cover. A mid-cycle refresh in 1977 with casting number 377131 with the one barrel carburetor base continued in production until 1979 but used a valve cover sized similarly to the conventional head with a shorter height, smooth face, and the PCV tube behind the oil fill hole (a known visual cue which IDs an integrated cylinder head is the position of the PVC breather tube; the truck/van integrated head 250s after 1978 had a taller valve cover with internal baffles). Light duty trucks c. 1978 - 1984 will have casting 14015499 (this one has the Varajet carburetor base - integrated intake runners are curved and incorporate a dual outlet exhaust manifold). |
But the detachable intake head (3895052, 3895054, 3927763, 83413880) can be fitted with a large variety of intake manifolds from the cast iron stocker to custom EFI (including multipoint fuel injection setups e.g. the use of Jeep 4.0 fuel injectors and the use of the Jeep throttle body requiring the use of a custom fuel rail and modifications to the intake manifold), IR, 4-barrels, staged 2 barrels, multiple carbs from Stromberg 94/97s to Weber's, to name a few. | But the detachable intake head (3895052, 3895054, 3927763, 83413880) can be fitted with a large variety of intake manifolds from the cast iron stocker to custom EFI (including multipoint fuel injection setups e.g. the use of Jeep 4.0 fuel injectors and the use of the Jeep throttle body requiring the use of a custom fuel rail and modifications to the intake manifold), IR, 4-barrels, staged 2 barrels, multiple carbs from Stromberg 94/97s to Weber's, to name a few. | ||
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