Vortec L31 cylinder head

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(Valve guide boss)
(Upgrading and compatibility)
 
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There are some inherent costs associated in swapping from 1995-back heads to the L31 Vortec heads. Here is a list of items to be purchased and/or labor associated with the upgrade:
 
There are some inherent costs associated in swapping from 1995-back heads to the L31 Vortec heads. Here is a list of items to be purchased and/or labor associated with the upgrade:
 
* L31 heads  
 
* L31 heads  
* Springs if the cam has a valve lift over about 0.420"
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* Springs if the cam has a valve lift over about 0.440"
 
* 1987 to present center bolt style valve covers if the heads used previously were perimeter style (1986 and earlier including the current production Goodwrench 350 crate motor)
 
* 1987 to present center bolt style valve covers if the heads used previously were perimeter style (1986 and earlier including the current production Goodwrench 350 crate motor)
 
** 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]]
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;From an article by editor Jeff Smith:
 
;From an article by editor Jeff Smith:
<blockquote>The Comp Cams cutter increases the spring-seat diameter while simultaneously reducing the outside diameter (OD) of the guide boss. The Crane tool also cuts the valve-guide-seal diameter at the same time. Comp sells a separate tool that cuts a new guide seal and reduces the guide height to create additional retainer-to-seal clearance. Both cutters machine the top of the guide down to a 0.530-inch diameter, which is the standard size for positive-type aftermarket seals. This requires purchasing new valve-guide seals, since the factory uses a 0.560-inch guide to locate the seals. Another way to go is to have a machine shop cut the guide boss diameter to around 0.760 inch and reduce the seal height and use either the Crane H-11 tool steel spring (PN 99846) or the Comp spring (PN 981).
+
<blockquote>The Comp Cams cutter increases the spring-seat diameter while simultaneously reducing the outside diameter (OD) of the guide boss. The Crane tool also cuts the valve-guide-seal diameter at the same time. Comp sells a separate tool that cuts a new guide seal and reduces the guide height to create additional retainer-to-seal clearance. Both cutters machine the top of the guide down to a 0.530-inch diameter, which is the standard size for positive-type aftermarket seals. This requires purchasing new valve-guide seals, since the factory uses a 0.555-inch guide to locate the seals. Another way to go is to have a machine shop cut the guide boss diameter to around 0.760 inch and reduce the seal height and use either the Crane H-11 tool steel spring (PN 99846) or the Comp spring (PN 981).
 
</blockquote>
 
</blockquote>
  
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<td class="wbg-blacktext" align="center" valign="top">Crane Cams valve spring and retainer kit. Drop-in springs with no machine work needed.</td>
 
<td class="wbg-blacktext" align="center" valign="top">Crane Cams valve spring and retainer kit. Drop-in springs with no machine work needed.</td>
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</tr>
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<tr class="wbg-blacktext" align="center" valign="top">
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<td class="wbg-blacktext" align="center" valign="top">Vsk4h53</td>
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<td class="wbg-blacktext" align="center" valign="top">Alex's Parts valve spring kit. Drop in fit, machine work not required up to .550" Lift, Hyd Roller.</td>
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</tr>
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<tr class="wbg-blacktext" align="center" valign="top">
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<td class="wbg-blacktext" align="center" valign="top">Vsk4h50</td>
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<td class="wbg-blacktext" align="center" valign="top">Alex's Parts valve spring kit. Drop in fit, machine work not required up to .550" Lift, Hyd Flat Tappet.</td>
  
 
</tr>
 
</tr>

Latest revision as of 23:22, 10 July 2020

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