Building an inline 6 Chevy 250 engine
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==Cylinder heads== | ==Cylinder heads== | ||
| − | + | The integrated intake head isn't well suited for performance duty. About all that can be done for a head with this intake, is the 1 barrel can be swapped for a 2 barrel by using an adaptor. Not the hot ticket. The lump port mods along with porting, larger valves, etc. can be done to ANY head, but without the ability to use a high performance intake, these mods would be largely wasted. | |
| − | + | Using the earlier head with the detachable intake from a 230 or 250 inline Chevy 6 offers a much better platform. Because of the current lack of aftermarket support for inline Chevy 6 cylinder heads, the hotrodder is left with the removable intake head from the early/mid '70s as the best choice for performance use, unless the cost of a custom head can be justified. | |
| − | ===Intake | + | In the past there were heads made for the Chevy 6. Now there are one-off heads for the Chevy inline 6 that have been made from 2 SBC aftermarket aluminum heads that have been divided and welded back together. |
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| + | ===Intake port mods=== | ||
The Chevy 250 head has a "3-port" intake. That means two ports are siamesed into a single port. This design, while fine for a daily driver or truck, leaves a lot to be desired for high performance work. | The Chevy 250 head has a "3-port" intake. That means two ports are siamesed into a single port. This design, while fine for a daily driver or truck, leaves a lot to be desired for high performance work. | ||
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Beginning in the mid-'70s, the inline 6 Chevy got an integrated intake cylinder head. 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. | Beginning in the mid-'70s, the inline 6 Chevy got an integrated intake cylinder head. 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. | ||
| − | + | But the detachable intake head can be fitted with a large variety of intake manifolds from the cast iron stocker to custom EFI, IR, 4-barrels, staged 2 barrels, multiple carbs from Stromberg 94/97s to Weber's, to name a few. | |
| − | + | The stock intake uses the exhaust manifold to provide heat to the intake, but if aftermarket exhaust headers and/or intake manifolds are used, this feature will be missing. For many applications that will see daily driver duty, an aftermarket intake equipped with hot water heating of the plenum is a plus. | |
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| + | If making all the power possible is the goal, an intake without hot water heating would be the better choice. | ||
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|[[File:4bbl inline int.jpg|thumb|350px|center|4-barrel inline 6 intake]] | |[[File:4bbl inline int.jpg|thumb|350px|center|4-barrel inline 6 intake]] | ||
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| + | ==Carbs== | ||
| + | The inline Chevy 250 was equipped with several different carbs through the years, from a single 1 barrel carb to a staged 2 barrel Rochester VaraJet carb. | ||
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| + | As mentioned in the Intake section, there are a large variety of aftermarket intakes that will accept an equally large number of carbs. | ||
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| + | One of the best carbs for a warmed-over 250 Chevy 6 is the 390 cfm Holley 4 barrel. It has enough flow for most applications, yet has good throttle response when used on smaller displacement engines. Repair and tuning parts are readily available and they're well understood by most rodders. | ||
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| + | The Weber induction set-ups are equally responsive, but at a much higher initial cost. | ||
==Timing gears== | ==Timing gears== | ||
| − | The Chevy inline 6 uses a pair of gears and no chain to turn the camshaft. There are high performance gear sets available from Comp and others. | + | The Chevy inline 6 uses a pair of gears and no chain to turn the camshaft. There are high performance gear sets available from Comp and others. The cam gear on aftermarket performance timing sets is often aluminum. |
| − | ==Exhaust | + | ===Exhaust manifolds=== |
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In the past, the stock exhaust manifold was "split" to run two exhaust pipes from the manifold. This helped performance, marginally. Eventually the aftermarket came out with manifolds made for the inline Chevy. | In the past, the stock exhaust manifold was "split" to run two exhaust pipes from the manifold. This helped performance, marginally. Eventually the aftermarket came out with manifolds made for the inline Chevy. | ||
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:[http://www.novaresource.org/codes.htm Engine codes], from NovaResource.com | :[http://www.novaresource.org/codes.htm Engine codes], from NovaResource.com | ||
:[http://www.adchevy.com/tools/castinglookup/ Casting number look up tool] and link to c/n lists from adchevy.com. | :[http://www.adchevy.com/tools/castinglookup/ Casting number look up tool] and link to c/n lists from adchevy.com. | ||
| − | :[http://www.inliners.org/tech/heads/headindex.htm 1962-up head casting numbers] from Inliners.org | + | :[http://www.inliners.org/tech/heads/headindex.htm 1962-up head casting numbers/chamber sizes ] from Inliners.org |
'''[[Building a Chevy 250 engine#Engine ID|Return to top]].''' | '''[[Building a Chevy 250 engine#Engine ID|Return to top]].''' | ||
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:[[Six cylinder inline engine parts and info sites]] | :[[Six cylinder inline engine parts and info sites]] | ||
| − | ==Parts | + | ==Parts and info== |
*[http://www.stoveboltengineco.com/ Langdon’s Stovebolt Engine Co.] | *[http://www.stoveboltengineco.com/ Langdon’s Stovebolt Engine Co.] | ||
*[http://www.cliffordperformance.net/index.html Clifford Performance] | *[http://www.cliffordperformance.net/index.html Clifford Performance] | ||
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