GT350 Aluminum Intake installation

[Corey Bowcutt]

I have removed my intake to clean things up and hopefully correct a problem.  But I have not done this since 1978 when I was a kid and then I did not sweat the details.  Is there a preferred gasket manufacturer I should go with or is the Fel-Pro listed on NPD as good as any?

Is there anything I should do special when installing the gaskets?  Should I put anything on the gaskets or the mating surfaces?  Should I put something in the joints between the side gaskets and the end gaskets?

Thank you,

Corey

[shelbydoug]

Fel-pro.

[Myred67]

I just installed my GT350 aluminum intake last year. I used the fel pro gaskets and the cork ends. Clean the intake and heads very well and make sure they are smooth. I used a DA sander on the intake side to clean it up.  Use weatherstrip adhesive to glue the cork pieces to the block first and let dry. I also used the copper spray on the side gaskets to help hold them to the block. Black RTV on the 4 spots that the cork meets the gaskets. About the size of a dime or less.  I believe most people advise using a thin layer of RTV around the water jackets as well. Make sure the intake drops straight down over the studs and doesn't move front or back while you start the torque sequence.

[shelbydoug]

One of the issues here is that there are two different cork thicknesses. The original one was thinner then virtually everyone you get in anyone's "kit" including Fel-pro,

The expensive issue is going to be that the COBRA aluminum intakes can be fragile on the rear two bolt holes and often we see repaired manifolds were those tabs have been cracked or even snapped off.

In order to use the current supplied cork ends you are going to need to compress them and I don't know how that you do that without clamping them down with the manifold?

If you want to risk that, that's up to you but that can be a VERY expensive mistake to damage that intake and I'll also point out that the rear water ports are where the gaskets like to leak sometimes internally where you don't see it.

You CAN use the cork ends but all things considered it is MUCH safer to trash them and just RTV the ends. However, it's your choice and neither is a mandatory decision. It's just you who has to regret not going the safer route.

[68gtcoupe]

One of the issues here is that there are two different cork thicknesses. The original one was thinner then virtually everyone you get in anyone's "kit" including Fel-pro,

The expensive issue is going to be that the COBRA aluminum intakes can be fragile on the rear two bolt holes and often we see repaired manifolds were those tabs have been cracked or even snapped off.

In order to use the current supplied cork ends you are going to need to compress them and I don't know how that you do that without clamping them down with the manifold?

If you want to risk that, that's up to you but that can be a VERY expensive mistake to damage that intake and I'll also point out that the rear water ports are where the gaskets like to leak sometimes internally where you don't see it.

You CAN use the cork ends but all things considered it is MUCH safer to trash them and just RTV the ends. However, it's your choice and neither is a mandatory decision. It's just you who has to regret not going the safer route.

+ 1 on ditching the cork end seals and going with RTV.  I've noticed that the aftermarket intake manufacturers (Edelbrock, Weiand) tell you to discard the cork end seals and use RTV in their instructions.


Terry

[Bob Gaines]

Some restorers take the cork end pieces and carefully slice them to half thickness and use them that way so that they can retain the factory type cork end pieces. This works for the majority of instances .  More work for sure compared to use just the RTV. This would only be more for the person concerned about wanting a solution for a effective yet original looking installation.

[68countrysedan]

Can I presume that SA used cork end seals during the original manifold installation?

How did that work out for them?

[shelbydoug]

Can I presume that SA used cork end seals during the original manifold installation?

How did that work out for them?

Yes but the original cork ends seem to be thinner, as Bob says, by about half.

I recently tried to go back to them and wound up doing the manifold installation three times.
First it leaked water, then oil and had a vacuum leak.

I was convinced the water and oil, was a bad head gasket which was a $90 Cometic one. Nope. Freakin' cork is what it was. It was all in the back against the firewall too so instead of it taking normal time, it took six times the effort since I had to do everything twice AND change the head gasket.

I even shimmed up the head bolts thinking they were too long and bottomed out?

Dumb, dumb and dummer.


A wise man will learn from the folly of others so as not to repeat it. Some of us become wise,,,sometime later.

I know the difference between self deprecating and self defecating. I'm embarrassed to admit, sometimes... not always, exactly which apples best to my case?


I just offer my experiences in order to save you from the same mistakes. But we can change the names in order to protect the innocent?

[Bob Gaines]

Can I presume that SA used cork end seals during the original manifold installation?

How did that work out for them?

You presume correctly regardless of if  Ford or SA installation of the intakes. Unlike fresh engines back in the day the engines of today many times have been rebuilt more than once. During rebuilding it is not uncommon for heads and blocks to be resurfaced. The resurfacing of one or the other or both complicates the fitment of a gasket on the front or back of the intake each time. That is why it is more of a issue now then back when the engines were first put together. 

[Corey Bowcutt]

This all sounds like really good advice. I really appreciate the help. I would really like this to work the first time. Would the permeated ultra black RTV be a good choice for the ends?
Corey

[Bob Gaines]

This all sounds like really good advice. I really appreciate the help. I would really like this to work the first time. Would the permeated ultra black RTV be a good choice for the ends?
Corey

If using the RTV I think it would. Basically any RTV will give good results but that one I have used with good results.

[warwick]

Fel-Pro sell sheets of cork in various thickness.  They refer to it as rubberized cork-it looks exactly like cork and was designed for us doing restorations. The Fel-Pro PN's are 3005, 3006 etc. You can get on Rockauto or Amazon.

[TLea]

The reason cork gaskets can be problematic is during engine rebuilds the block decks and heads get milled which draws intake mating surfaces away from intake and manifold can't go down far enough with fixed cork gaskets. Skilled engine builders will machine bottom of intake to compensate. On a FE this will allow valve cover to seal better because top of intake and head will be flush

[shelbydoug]

The reason cork gaskets can be problematic is during engine rebuilds the block decks and heads get milled which draws intake mating surfaces away from intake and manifold can't go down far enough with fixed cork gaskets. Skilled engine builders will machine bottom of intake to compensate. On a FE this will allow valve cover to seal better because top of intake and head will be flush

That is certainly true but not the entire answer. The current aftermarket, including Felpro seem to be just too thick even on reassembling an intake where nothing has been milled or resurfaced.

I think it's important to illustrate the "risks" involved in attempting to use them and the alternatives so that those in need can make an informed decision.

[pbf777]

During rebuilding it is not uncommon for heads and blocks to be resurfaced. The resurfacing of one or the other or both complicates the fitment of a gasket on the front or back of the intake each time. That is why it is more of a issue now then back when the engines were first put together.

The reason cork gaskets can be problematic is during engine rebuilds the block decks and heads get milled which draws intake mating surfaces away from intake and manifold can't go down far enough with fixed cork gaskets. Skilled engine builders will machine bottom of intake to compensate. On a FE this will allow valve cover to seal better because top of intake and head will be flush

That is certainly true but ......................

     Not to be at odds with anyone, but this is not correct     

     The intake face of the cylinder head is machined at 90° to the deck surface, and each of these cylinder head intake mounting surfaces are 90° to one another, therefore the overall intake meeting surfaces do not change in distance from one another with the proper machining of the cylinder head or block decking surfaces.     

     Now, an effect of the cylinder head intake faces siding downward in alignment under the intake manifold, but still in the same plane of parallelism and distance, will be witnessed as either of the decks are surfaced.  If in order to correct this to some degree, one then machines or surfaces the intake manifold faces so as to cause it to "sink" in its' relationship to the cylinder head faces this correcting for better inlet port and bolt hole alignment (except in the S.B.F. as the bolt holes for the intake manifold retention are vertical & note that those with bolt holes at divergent angles may not recover simultaneously with other alignment concerns), and this does change the position of the intake manifold in its' relationship to the cylinder block "china-wall".     

     And before someone chooses to blast me out of the water, think-about-it!     

     Scott.