Sealing the 383 intake manifold

Sealing the 383 intake manifold - 10/15/14 06:39 AM

Ref: '70 383 HP with stock cast 4 bbl intake.
Having trouble with bolt alignment on intake while using gasket/valley pan/gasket. QUESTION: Can I get a proper seal by just using the valley pan between the heads and the intake manifold?

Posted By: calrobb2000

Re: Sealing the 383 intake manifold - 10/15/14 06:49 AM

hi
stock cast intakes do not use any gasket other than the valley pan !

Posted By: 69/70 Plymies

Re: Sealing the 383 intake manifold - 10/15/14 07:02 AM

Quote:

hi
stock cast intakes do not use any gasket other than the valley pan !

Are you kidding me? No wonder I'm having trouble. Gaskets were on the engine when I tore it down before the rebuild. Are the gaskets only used on aluminum intakes?

Posted By: Pynzo

Re: Sealing the 383 intake manifold - 10/15/14 11:41 AM

I used permatex ultra copper rtv and it sealed up nice.

Posted By: skicker

Re: Sealing the 383 intake manifold - 10/15/14 01:08 PM

I was told to use the additional gaskets when installing an aluminum intake. I did and it leaks a little. When I pull it back apart I'm just using the metal valley pan gasket.

Posted By: therocks

Re: Sealing the 383 intake manifold - 10/15/14 01:34 PM

Since the 60s Ive just used the tins.Even on my 440 alum heads and intake its just tin.No leaks ever.Rocky

Posted By: 69/70 Plymies

Re: Sealing the 383 intake manifold - 10/15/14 02:28 PM

If a person does use the Copper RTV, do you apply it around all ports and on all connecting surfaces?

Posted By: skicker

Re: Sealing the 383 intake manifold - 10/15/14 02:57 PM

Quote:

If a person does use the Copper RTV, do you apply it around all ports and on all connecting surfaces?

That's what I did except I used the black rtv.

Attached picture 8300925-Offy360intakemanifold.jpg

Posted By: Pynzo

Re: Sealing the 383 intake manifold - 10/15/14 04:06 PM

Yes both sides of the pan for the intake to head seal and bottom side front and rear edges of pan to seal the block. Copper works with the street Hemi orange engine paint. Any extra that squeezes out blends in nicely. Blue or black would be a pita to clean up.

Posted By: 69/70 Plymies

Re: Sealing the 383 intake manifold - 10/15/14 06:23 PM

Just trying to get to the bottom of this question....Were the original 383 intake manifolds from the factory in 1970 with gasket/valley pan/gasket or just valley pan? I have seen both claims, which is correct?

P.S. The shop wants me to mill the intake in order to get proper intake bolt alignment and use the paper gaskets along with the valley pan per AERA's and Hughes Engine's recommendations.

Pynzo...10-4 on the use of the copper, matches the paint just like you say!

Posted By: streetkit

Re: Sealing the 383 intake manifold - 10/15/14 06:45 PM

No paper gaskets from the factory. Valley pan only.

Posted By: stumpy

Re: Sealing the 383 intake manifold - 10/15/14 06:46 PM

Tin only form the factory.

Posted By: MoparforLife

Re: Sealing the 383 intake manifold - 10/15/14 06:47 PM

They were just the pan. No Paper. RB motors the same. Just the valley tin.

Posted By: JohnRR

Re: Sealing the 383 intake manifold - 10/15/14 07:47 PM

Quote:

Quote:

If a person does use the Copper RTV, do you apply it around all ports and on all connecting surfaces?

That's what I did except I used the black rtv.

You better pray you don't have to take that intake off , ever ... it's going to be a mess getting that off .

OP , the paper gaskets that come with the valley tin are .030 thick EACH , of course you will have alignment issues.

I like to use an .015 thick gasket to help seal because I hate having to scrap off sealer So I usually have .015 taken off the intake so I can use them .

Posted By: JohnRR

Re: Sealing the 383 intake manifold - 10/15/14 07:48 PM

Quote:

No paper gaskets from the factory. Valley pan only.

Posted By: sthemi

Re: Sealing the 383 intake manifold - 10/15/14 10:40 PM

Factory used only the tin gasket.

I have reused them many times with no sealing issues.
Normally I install them dry, except for the "V" area by the corners, where I put a dab of RTV sealer.

Tin gasket works well with both alum and iron intake. The paper shims are only to be used to space up an intake that has been decked (milled) to correct any mismatch.

Posted By: RapidRobert

Re: Sealing the 383 intake manifold - 10/15/14 11:18 PM

Quote:

The shop wants me to mill the intake in order to get proper intake bolt alignment and use the paper gaskets along with the valley pan per AERA's and Hughes Engine's recommendations.

As said they came from Ma with just the tin & many were good for years and people have used em bare and with gaskets. The Felpro gaskets are ~.030" iirc and the superformance gaskets are .015". What works for me is to confirm the head intake surface and the manifold surfaces are flat & use the .015" gaskets with some Permatex 99MA spray gasket adhesive "high tack" the red spray on stuff. On initial mockup I brush some dykem horizontally along the top and bottom of the head and intake ports with a turn up on the ends (you'll grasp that when you get there) and scribe a line in the dye with a scribe and a metal ruler for a straight horizontle line then mockup the intake/valley pan/paper gaskets in place dry and compare the height of the scribed lines at the turned up ends & see how far down the "slope" the intake has to come down further into the "V" for the ports to be in good alignment then I give that number to the shop & let them do the math. If you're gonna mill you might as well take some extra time & get the port alignment dead on (the butt dyno will feel it). this means the head/intake gasket surfaces are flat/port alignment is good/paper gaskets help the tin seal

that way everything in that system is spot on. I take a skim cut on the intake if needed and then cut the head intake surface to achieve alignment that way the intake ain't specific to that eng (helpfull if it is an alum one that might get changed/sold at a later date). If iron I might take it all off of the intake if the head intake surface is flat as likely that intake will be there forever. EDIT I prefer using paper with the tin and port (& especially bolt hole) alignment will dictate whether you can use paper or not without milling. OE deck height/ Head/intake prior milling/head gasket thickness can be anywhere (mockup/measure twice)