454 intake manifold gaskets not sealing

[Slooptin]

After suspecting that my oil consumption + low vacuum issue was the result of bad intake manifold gaskets, I was able to confirm that that was the case (see pics). Basically I had a leak under the manifold that was simultaneously sucking oil into the intake ports and not letting me get past 15-16 in of vacuum (stock motor). It looks like it just wasn’t sealed on both sides at the bottom so I’m weary about just putting new gaskets in since something is telling me that both bottom areas not sealing is a sign of a bigger issue, i.e. the manifold not lining up with the intake surface of the heads. Is there any way to verify that a new gasket will seal?

 

[Rickf]

There is a difference between "peanut" port and round port gaskets.

 

[Slooptin]

Enough of a difference to cause this much leakage?

 

[Ricko1966]

How and when did this problem start. I ask because if the heads have been milled very much you need to remove material from the intake side of the head also to get the manifold to sit right. Yes you can modify the manifold but then those heads and manifold are a matched set. If you mod the heads any standard manifold will bolt on.

 

[nvrenuf]

Specifically where are you seeing evidence of leaks? You didn’t post pics of all of the ports but the blue sealing rings look to be intact and I don’t see any oil trails running across them.

The intake pic is at such an angle I can’t really see the gasket imprint on it.

 

[Turbo4whl]

Hard to tell from the pictures. Are they the 454 peanut port heads and the manifold is for the large oval ports?

 

[fast 99]

Make sure the gaskets are correct for the heads. Agree gaskets don't appear compromised. Lay the intake back on it. Check the china wall, there should be some gap. If not the heads have been milled too many times. Intake will need to be machined to match.

 

[Ricko1966]

Another thing to check,bolt the manifold to one head only,now look at the gap on the other head,are the manifold and cylinder intake flange parallel top to bottom,is the gap greater than the thickness of 2 compressed intake gaskets? Making sure the heads haven't been angle milled.

 

[Rusty Nail]

I started lookin at those pictures because I expected to see the intake manifold. But wtf?

 

[nvrenuf]

The last pic is the intake but they’re still awful.

 

[Slooptin]

Sorry for the dogshit pics. But the lower part of both gaskets is wet with oil. Oil is also fresh because I’ve been having to constantly refill as I drive. I checked all 4 surfaces for flatness and they’re true as far as I can tell. Also no machining on heads that I’m aware of

 

[Snoots]

You have to clean the intake and heads cleaner than a new babys' butt first. Anything less and the door is wide open for problems.
Take the old gaskets in to the store and make certain they match what you have. Use Fel-Pro and don't forget a hi-temp RTV for the china wall.
If I remember correctly the torque is 25 ft-lbs in a particular sequence. Look it up and follow it.

 

[hogdaddy]

You have to clean the intake and heads cleaner than a new babys' butt first. Anything less and the door is wide open for problems.
Take the old gaskets in to the store and make certain they match what you have. Use Fel-Pro and don't forget a hi-temp RTV for the china wall.
If I remember correctly the torque is 25 ft-lbs in a particular sequence. Look it up and follow it.

I like to chase all thread holes too and put thread sealant on cleaned bolts.

 

[Rusty Nail]

If you checked them for flatness and it's true than the manifold is bowed. Tell me about the manifold..is is it iron or aluminum?
You will have to use tempera paint or something...I bet it's bent. Checking one side for trueness and then the other will NOT tell you it's bent.

"how do you bend an intake manifold?"

Bolts too tight, overheating, improper tightening sequence..all of the above or a combination?
Do you assert it's not possible?
Might wanna figure out a way to determine that.

 

[Ricko1966]

Are you sure you are using the correct length intake bolts just a little but too long and the boltsvwill get tight,but not compress the gaskets.