The good vs bad chevy vortec heads - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 09-18-2009, 03:48 PM
Registered User
 
Join Date: Oct 2006
Location: Louisiana
Posts: 15
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The good vs bad chevy vortec heads

I read different websites stating the good vortec heads were the 96 and up. I found a 96 suburban and pulled the heads. I just read the casting and these are supposedly the bad heads.
Can someone clear up what vehicles the good castings came on?
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 09-18-2009, 04:17 PM
heathj1's Avatar
Which way to the swap meet??
 
Join Date: Dec 2008
Location: iowa
Posts: 68
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
906 and 062 are vortec heads. I thought they came on trucks. What are your casting numbers?
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 09-18-2009, 05:00 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 6,437
Wiki Edits: 0

Thanks: 3
Thanked 331 Times in 288 Posts
Quote:
Originally Posted by stevenf
I read different websites stating the good vortec heads were the 96 and up. I found a 96 suburban and pulled the heads. I just read the casting and these are supposedly the bad heads.
Can someone clear up what vehicles the good castings came on?
You need to tell us the casting numbers. 305 engines don't use the "Vortec" head, they use the standard 305 head but GM called it a Vortec but it does not have the chamber and port features of the L31 heads.

Not all 96 models got the 350 Vortec engine. If a California vehicle then its for sure OBD II and if a 350 also with Vortec heads and Central Port Sequential Injection and a roller Vortec block, casting ends in 880. If it's a 49 state, early production could be full up OBD II Vortec or OBD I TBI on Swirl Ports with a roller Vortec block, or could be OBD I TBI on Vortec heads and a roller Vortec block. As the production year proceeded eventually all 350 output got the L31 Vortec. Generally for early production the half tons got the full Vortec treatment, the heavy duty models 3/4 and up is where you usually see the Swirl Port head with TBI or the TBI variations on a Vortec head.

The L31, 350 uses two castings, either makes the same part number 125508060, the castings that make this P/N are 10239906 or 12558062. The difference between them is how the exhaust seat is wear treated the 906 uses hard seat inserts while the 062 uses induction hardening of machined in the casting seat.

Generally the 906 is considered to be a lower flowing exhaust port design, but this is only a consideration for a flat out, total performance motor and to get either of the P/N --060 Vortec heads to that point takes a lot of work to the spring pockets, valve guides, stem seals, roller rockers, beehive springs, screw in studs, steel push rod guides, porting, etc. These are such extensive modifications to allow the valves the movement and control to accept a competition level cam, that if you're not going that far, the minor difference in port flow between the 906 and 062 castings is absolutely of no consequence to you because you'll never push the stock or near stock head anywhere close to the port's flow capability. Plus it isn't good in a non-race engine to have too much exhaust capability, This causes all sorts of intake problems when the cylinder is over scavenged which drives you into really having to trim and specialize the intake manifold and carb, otherwise the engine's power curve takes an early and big nose dive that few people, except for a handful of race tuners understand how to compensate for without just reverting to an exhaust system that develops more back pressure.

These days there are better solutions to the maximum performance head than using old Vortecs, to put the kind of effort and money into L31 heads for a race motor is a simply a wasted effort. But for a sturdy, solid good performing street motor, these heads are tough to beat regardless of the casting chosen. So if that's where your going don't let these guys that gaze at flow bench numbers and make pronouncements as to what's good and what isn't influence your thinking. There's a lot more to consider in head selection than how many CFMs your mother's vacuum cleaner can suck thru a port.

Bogie

Last edited by oldbogie; 09-18-2009 at 05:32 PM.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 09-18-2009, 05:21 PM
Registered User
 
Join Date: Oct 2006
Location: Louisiana
Posts: 15
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
These are from a 96 suburban 350(5.7). It has the 906 Casting which is the bad ones. Just trying to clear up what the good heads came on because its not all 96+ like I read on a few other sites.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 09-18-2009, 05:27 PM
BOBCRMAN@aol.com's Avatar
Member
 
Last photo:
Join Date: May 2002
Location: Holly, michigan
Posts: 7,954
Wiki Edits: 0

Thanks: 13
Thanked 218 Times in 207 Posts
The good head bad head thing was started many years ago by an article in Car Craft magazine. They later recanted the story.

I work on these heads regularly and about the only differences are most of the 906 heads have hardened seat inserts in the exhaust. These can be made to flow very well with a competent three angle and some bowl blending.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 09-18-2009, 05:36 PM
Registered User
 
Join Date: Oct 2006
Location: Louisiana
Posts: 15
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
What a relief it is to read that. Spent a good while pulling these things. First time going that far into an engine and discovering all 4,000,000 bolts holding on each head is a task all its own.
Is the three angle job done to round out the valve cylinder? How much does that usually cost and how big a job?
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 09-18-2009, 05:57 PM
Registered User
 
Last photo:
Join Date: Apr 2007
Location: Seattle, Wa
Posts: 6,437
Wiki Edits: 0

Thanks: 3
Thanked 331 Times in 288 Posts
Quote:
Originally Posted by stevenf
What a relief it is to read that. Spent a good while pulling these things. First time going that far into an engine and discovering all 4,000,000 bolts holding on each head is a task all its own.
Is the three angle job done to round out the valve cylinder? How much does that usually cost and how big a job?
The 3 angle valve job is shop standard. It is usually a 45 degree seat with a 30 degree top cut and a 60 degree cut in the throat. The top and bottom cuts position the seat and valve, determine the width of the seat and provide a smoothing transition for the flow as it approaches and departs the seat. Generally the maximum the flow can turn 15 degrees without separation from the wall so a three angle is the minimum you can get away with unless performance is penalized. Performance valve jobs often take this to 5 cuts, but for a street engine the cost isn't justified. Keep in mind that cutting seats sinks the valve, this makes the combustion chamber bigger in volume which reduces compression and makes the valve stem appear longer to the valve spring reducing its pressure. While the spring can be shimmed to recover the pressure, there's nothing to be done for compression short of changing pistons and or valves to refill the additional space with something. You can go to new valves, especially larger valves, that require the seat to be moved into fresh material for a complete recovery. The guides need to be inspected for stem clearance and corrected if necessary, this needs to be done before doing the seats. You need to talk with your local shop, this stuff gets expensive pretty quickly, which is why new Vortecs are so popular since you can drive the cost of rebuilding heads well into the cost of new ones without much effort.

Bogie
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 09-18-2009, 06:18 PM
Registered User
 
Join Date: Jan 2008
Location: omaha nebraska
Posts: 148
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
i have a pair of new vortec heads on a 406 chevy and they seem to flow and perform really well. also the price of the pair assembled was 950 total...hard to beat that for brand new!
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 09-18-2009, 11:46 PM
Registered User
 
Join Date: Oct 2006
Location: Louisiana
Posts: 15
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
So would you say its worth it to get the 3 angle valve job on these bad casting number vortec heads? Or would I be better off finding another set of correct casting?
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 09-19-2009, 09:57 AM
Registered User
 
Last photo:
Join Date: Jan 2007
Location: canada
Posts: 564
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
906 heads aren't bad or wrong castings
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 09-19-2009, 10:56 AM
artsvettes's Avatar
Registered User
 
Last photo:
Join Date: Aug 2006
Location: New Jersey
Posts: 160
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by va4cqd
906 heads aren't bad or wrong castings
I agree I am running 2 sets of 906 on diffrent engines
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 09-19-2009, 02:59 PM
techinspector1's Avatar
Senior Curmudgeon
 
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Hemet, California, USA
Age: 72
Posts: 12,246
Wiki Edits: 326

Thanks: 602
Thanked 767 Times in 657 Posts
Quote:
Originally Posted by stevenf
bad casting number vortec heads?
Please stop saying that, there is no good or bad, there is only DIFFERENT relating to the valve seats.

I'm going to go out on a limb here and paste a response that I gave to a member on another forum relating to L31 heads...

"Hey flanker, I'm not trying to spend your money and I love L31 Vortec's flow characteristics for a street/strip motor, but you should consider the following.
Don made us aware of a new offering from Edelbrock, a cylinder head that is brand new, cast in aluminum, treated to T6, about the same published flow numbers as the L31, good springs, guide plates, screw-in studs installed on heli-coils and hardened spring cups between the spring/casting, stainless/one-piece/hard-tip valves and a fire sale price of $950 retail for the pair, assembled, ready to bolt on.
http://www.edelbrock.com/automotive_...e-street.shtml

Compared to that, consider the initial cost of L31's, cost of magnaflux to find out if they're cracked or not. If they are, then a hassle with the boneyard/seller. If they aren't, then further money to cut the decks for flat, machine the valve guides and/or seats for decent springs, cost of the springs/retainers/locks, a new valve job, remove pressed-in studs. Machine stud pads. Drill and tap for screw-in studs, cost of the studs, all the labor involved, yada, yada, yada. And you end up with a ton of money in cast iron production heads that may still be crack-prone once you get 'em bolted on.

Like I said, it's easy to spend your money, but as for me, I likely won't be scrounging for L31's any more. Not after I put a price on searching for/going to see/cost of my time and my vehicle costs running around, cleaning/machining, etc, etc. One phone call and the Edelbrocks are delivered to my front door."

Last edited by techinspector1; 09-19-2009 at 03:13 PM.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 09-19-2009, 06:58 PM
cool rockin daddy's Avatar
1.21 giga-watts???!!!!
 
Join Date: Aug 2003
Location: wherever cool cars are
Posts: 1,535
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
Geez, dude. Take the freakin' vortec heads you got to a machine shop and tell them you want a three angle valve job put on them. They'll work fine. You could probably have the heads magnafluxed, bowl blended, and three angle valve job done for around $400 bucks. Any more, spend the dough on some new aluminum heads or better yet, Bowtie Vortecs. Quit worrying already. You scored some great heads for a street motor. I really don't understand all this "buyers remorse" AFTER somebody has bought something. Do your research before you buy or climb all over some junkyard car looking for parts and you don't have this problem. Vortecs have been out now for THIRTEEN YEARS!!!!!!
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 09-19-2009, 10:12 PM
Registered User
 
Last wiki edit: How to title a hot rod Last photo:
Join Date: Feb 2007
Location: West Virginia
Age: 24
Posts: 3,389
Wiki Edits: 8

Thanks: 14
Thanked 1 Time in 1 Post
Quote:
Originally Posted by SBCfan04
i have a pair of new vortec heads on a 406 chevy and they seem to flow and perform really well. also the price of the pair assembled was 950 total...hard to beat that for brand new!
I also have a pair of new RHS Vortec heads on a 406,runs really strong,assembled was around $480
Shane
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 09-20-2009, 01:22 AM
curtis73's Avatar
Hates: Liver. Loves: Diesel
 
Last wiki edit: How to find cheap parts
Last journal entry: 1999-2001: Getting it on the road
Last photo:
Join Date: Dec 2005
Location: Pittsburgh, PA
Age: 40
Posts: 5,128
Wiki Edits: 16

Thanks: 0
Thanked 1 Time in 1 Post
The two castings are similar enough that I had no problems running one 906 and one 062 on the same engine. Plugs read the same, power is great, compression is even in all cylinders.

Same head, different valve seat.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 5 (0 members and 5 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
chevy 350 vortec heads ....wat cam?? 47chevrolet Engine 9 09-04-2007 03:12 PM
vortec vs phase 2 heads 71vegagt Engine 3 01-29-2006 05:12 AM
vortec heads on sbc 400 camino_man Engine 16 11-11-2005 01:33 AM
Camshaft for vortec heads Leon Weathers Engine 3 11-19-2004 10:02 PM
NEW GMPP VORTEC heads !! terror385 Engine 1 07-11-2004 09:48 AM


All times are GMT -6. The time now is 12:57 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.