Vortec L31 cylinder head
(→Flow rate of L31 Vortec heads: format table) |
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* Springs if the cam has a valve lift over about 0.420" | * Springs if the cam has a valve lift over about 0.420" | ||
* Center bolt style valve covers if the heads used previously were perimeter style | * Center bolt style valve covers if the heads used previously were perimeter style | ||
| − | ** Note: [http://www.crankshaftcoalition.com/wiki/Vortec_L31_cylinder_head#Small_port_Vortec_head_p.2Fn_25534351_.28bare.29_and_p.2Fn_25534421_.28assembled.29 GMPP small and large port Vortec heads] and other aftermarket Vortec heads accept either perimeter or center bolt valve covers[[File:Vortec valve-rocker.jpg|thumb|right|300px|Self aligning stamped steel rockers]] | + | ** Note: [http://www.crankshaftcoalition.com/wiki/Vortec_L31_cylinder_head#Small_port_Vortec_head_p.2Fn_25534351_.28bare.29_and_p.2Fn_25534421_.28assembled.29 GMPP small and large port Vortec heads] and other aftermarket Vortec heads accept either perimeter or center bolt valve covers [[File:Vortec valve-rocker.jpg|thumb|right|300px|Self aligning stamped steel rockers]] |
*Self aligning rocker arms | *Self aligning rocker arms | ||
* Valve cover gaskets | * Valve cover gaskets | ||
| − | * Vortec specific intake manifold. While some aftermarket heads have both 12 and 8 bolt intake bolt patterns, the height of the Vortec ports require a tall, "raised port" type early intake manifold (along with porting/port work to the intake manifold and/or head), to even come close to fitting correctly | + | * Vortec specific intake manifold. While some aftermarket heads have both 12 and 8 bolt intake bolt patterns, the height of the Vortec ports require a tall, "raised port" type early intake manifold (along with porting/port work to the intake manifold and/or head), to even come close to fitting correctly. See '''[[Vortec_L31_cylinder_head#Using an early style intake on an aftermarket Vortec-type head|Using an early style intake on an aftermarket Vortec-type head]]''' for more info |
* Vortec specific intake manifold gasket | * Vortec specific intake manifold gasket | ||
* Vortec specific intake manifold bolts | * Vortec specific intake manifold bolts | ||
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====Large port Vortec flow chart==== | ====Large port Vortec flow chart==== | ||
| − | <table border="5" cellspacing="0" cellpadding="5"><tr valign="top" tr bgcolor="#CCCCFF"><td colspan="2"><center>INTAKE</center></td><td colspan="2"><center>EXHAUST</center></td></tr><tr valign="top" tr bgcolor="#FFF8DC"><td>Lift (in.)</td><td> CFM </td><td>Lift (in.)</td><td> CFM </td></tr><tr valign="top"><td>0.200</td><td>128.6</td><td>0.200</td><td>100.8</td></tr><tr valign="top"><td>0.300</td><td>188.4</td><td>0.300</td><td>138.6</td></tr><tr valign="top"><td>0.400</td><td>234.8</td><td>0.400</td><td>154.4</td></tr><tr valign="top"><td>0.500</td><td>257.2</td><td>0.500</td><td>152.5</td></tr><tr valign="top"><td>0.600</td><td>263.2</td><td>0.600</td><td>163.8</td></tr><tr valign="top"><td>0.700</td><td>269.1</td><td>0.700</td><td>167.0</td></tr></table> | + | <table border="5" cellspacing="0" cellpadding="5"><tr valign="top" tr bgcolor="#CCCCFF"><td colspan="2"><center>'''INTAKE'''</center></td><td colspan="2"><center>'''EXHAUST'''</center></td></tr><tr valign="top" tr bgcolor="#FFF8DC"><td>'''Lift''' (in.)</td><td> '''CFM''' </td><td>'''Lift''' (in.)</td><td> '''CFM''' </td></tr><tr valign="top"><td>0.200</td><td>128.6</td><td>0.200</td><td>100.8</td></tr><tr bgcolor="#F1F1F1" valign="top"><td>0.300</td><td>188.4</td><td>0.300</td><td>138.6</td></tr><tr valign="top"><td>0.400</td><td>234.8</td><td>0.400</td><td>154.4</td></tr><tr bgcolor="#F1F1F1" valign="top"><td>0.500</td><td>257.2</td><td>0.500</td><td>152.5</td></tr><tr valign="top"><td>0.600</td><td>263.2</td><td>0.600</td><td>163.8</td></tr><tr bgcolor="#F1F1F1" valign="top"><td>0.700</td><td>269.1</td><td>0.700</td><td>167.0</td></tr></table> |
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==Vortec intake manifolds== | ==Vortec intake manifolds== | ||
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Because of these differences, a Vortec-specific intake should be used. | Because of these differences, a Vortec-specific intake should be used. | ||
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;Chevrolet says<nowiki>:</nowiki> | ;Chevrolet says<nowiki>:</nowiki> | ||
<blockquote> | <blockquote> | ||
Do not try to modify either the heads or the intake manifold to try to make the Vortec heads match up to a standard 12-bolt intake manifold. The ports will not match up. You must use a Vortec style intake manifold with any Vortec style cylinder head. | Do not try to modify either the heads or the intake manifold to try to make the Vortec heads match up to a standard 12-bolt intake manifold. The ports will not match up. You must use a Vortec style intake manifold with any Vortec style cylinder head. | ||
</blockquote> | </blockquote> | ||
| + | ;Return to '''[[Vortec_L31_cylinder_head#Upgrading and compatibility|''Upgrading and compatibility'']]''' | ||
| + | ==Intake gaskets== | ||
Due to issues with some Vortec intake manifold gaskets (vacuum and coolant leaks), it is suggested to use a Fel-Pro gasket p/n Q1255 intake gasket, or equivalent. | Due to issues with some Vortec intake manifold gaskets (vacuum and coolant leaks), it is suggested to use a Fel-Pro gasket p/n Q1255 intake gasket, or equivalent. | ||
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* [http://www.chevyhiperformance.com/howto/97458/index.html Iron Vortec Head All the Details You Need to Know] from the February, 2009 issue of ''Chevy High Performance''. | * [http://www.chevyhiperformance.com/howto/97458/index.html Iron Vortec Head All the Details You Need to Know] from the February, 2009 issue of ''Chevy High Performance''. | ||
*[http://www.pacificp.com/forum/viewtopic.php?t=8710&postdays=0&postorder=asc&start=0&sid=c924276423ef14adb8e81be996202589 Using the LT4 Hot Cam] hydraulic roller camshaft in a Vortec engine | *[http://www.pacificp.com/forum/viewtopic.php?t=8710&postdays=0&postorder=asc&start=0&sid=c924276423ef14adb8e81be996202589 Using the LT4 Hot Cam] hydraulic roller camshaft in a Vortec engine | ||
| + | *[http://users.erols.com/srweiss/tablehdc.htm#Chevy Chevy head flow] from S. Weiss | ||
==Resources== | ==Resources== | ||
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