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Vortec intake manifold torque specs?
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Post Vortec intake manifold torque specs? 
Hello: I have a Gen 1 Chevy 350 in my 76 Monte. I have removed the stock heads and put on vortec heads. I am putting a GM vortec intake manifold on as well. I'm not sure how old the vortec heads or manifold is but I think they came from a ZZ Crate engine (?). Anyone have any idea what the torque specs are in foot-pounds for the manifold? Manifold is stamped with GM12486570...I know the torque specs won't be the same as my Haynes manual states, as the heads and manifold are not stock...
Thank you in advance for any help!!

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Post Vortec intake torque specs 
Not foot-pounds!

INCH-POUNDS!!!

I highly recommend the FEL-PRO MS98000T with Aluminized steel carrier and apply a thin coat of RTV for a permanent seal around the coolant ports


1st pass 27 in-lb
2nd pass 106in-lb
3rd Pass 132in-lb (11 ft-lb is usually too small for a ft-lb torque wrench)

Torque pattern:




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looks like I will need to get a inch-pound torque wrench...my torque wrench is only in foot pounds :(

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I highly recommend those metal Fel-Pro gaskets as well, and for the front and rear "China Wall" on the block, use Permatex RIGHT STUFF black RTV.

I've found "Right Stuff" to be far superior to even the "Ultra Black" RTV. The above combo is the ONLY way to fly on Vortec manifolds.

Also, clean ALL the old threadlock off of the lower intake manifold bolts and use Permatex Medium Strength (#242) Blue threadlock when re-assembling. With those metal Fel-Pro gaskets, you can go up on the torque spec just a bit over the stated spec. I recommend going a bit tighter, nothing crazy though.





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Yes!
Permatex RIGHT STUFF black RTV. 

X2

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The current GM Design (circa 2004) is improvements to all the failure points of the original design. I have these in every L31 I take care of and have not yet had a single failure. You can see the differences between the original (fragile) design on the left below and the current on the right. The new design includes metal inserts to prevent crushing of the plastic, which ironically the BBC L29 version included from day 1.



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Here are a few failure pics of three different trucks from the past for everyone's amusement:

















The current design:


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Those aren't even the most revised version.

The l18 gaskets are same design and new design is steel/rubber no plastic

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Whipped383 wrote:
Those aren't even the most revised version.

The l18 gaskets are same design and new design is steel/rubber no plastic


Perhaps GM is deciding to finally wise up then. I actually have seen the "revised" plastic GM gaskets fail too, although not as thoroughly as the original plastic design. The revised gaskets don't collapse and allow a coolant leak as badly as the originals, but the last set I pulled off were not sealing well around the intake ports at all... had lifter valley oil getting sucked into the ports. Just not enough of a sealing bead there which is part of the reason I like the Fel-Pros... they just have so much more surface area dedicated to sealing both the coolant ports AND the intake ports, not to mention the greatly increased robustness intrinsic to the metal frame.

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Got the manifold on today...thanks for everyone's help/advice...I needed it!

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putting on headers as well...anyone know what the torque sequence is for headers onto vortec heads? 11 ft pounds?

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Header torque... I don't know that. I've been using stainless studs for years successfully. If your headers came with composite or laminated header gaskets of any type throw those out - they are all terrible. Reuse the OEM stainless multi-layer gaskets with your headers; they will never fail and will not need retorquing.

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Don't remember the number, but the sequence is you start with the two inside ones and work your way out. 33 foot lbs seems to pop into my head although I wouldn't guarantee it.

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