Edelbrock intake manifold install.

[Mike65 475]

Tomorrow I will be installing the Edelbrock Performer RPM intake on my 1987 5.0 engine, the Edelbrock paper work I printed on line says not to use the cork or rubber end seals to just use a 1/4" bead of RTV silicone sealer instead. The last aluminum intake I installed I used the cork end seals with out any problem, the gasket set I have has the rubber end seals. What does everyone think?. Here is the link to the install instructions.

https://www.jegs.com/i/Edelbrock/350/7121/10002/-1

[70Mach1rb 1]

A great question that many come to ask.

In my opinion as a retired mechanic, you should always use cork if you need a seal. Plus silicone sealant. In many instances. The sealant helps hold gaskets in place. 

Cork works, it has been working for over 100 years.

As far intakes it depends on the depth gap you are going to close. Bigger gaps require more material to make the seal. The end gaskets can be omitted entirely if there is no more than a 1/8 gap. In that case, you could get by with a good rtv sealant. If your gap is larger say 3/16 or more after torquing intake bolts I would indeed use the rubber seal provided. Most of us are not qualified engineers. 

There should never be much of a problem with intakes and getting them to seal. If there's a big gap put a seal there. Add sealant. If not a large gap, you can use a gasket making sealer. But everyone will tell you something different. Also that if you use a rubber seal do not use sealant. Many will still add a glob at the corners. And that makes some sense in that leaks are generally coming from the corners.

I normally see most people using what the parts come with. And it just makes sense not to have to go to the store again. And no, you don't always need a sealant. But if it doesn't hurt anything it can actually be a life saver.

[1969_Mach1 333]

First, make certain you are using a performance intake gasket set, like the Fel-Pro 1250, 1250S3 which is a steel core version of the 1250, Edelbrock 7220, etc. The Edelbrock 7220 seems to last longer on a street car than the Fel-Pro 1250.  Aftermarket intake sometimes do not fit as well as OEM and once in a while a stock replacement intake gasket will not seal an aftermarket aluminum intake manifold.  Lastly, regarding the end seals I would install it per the instructions using RTV unless the end gaps are large like 70Mach1rb mentions.  Once in a while, if the end gaps are small, cork end seals will prevent the aluminum intake from properly sealing to the cylinder heads.  OEM intakes don't seem to have these issues.

[Brian Conway 264]

Before laying down the gaskets and sealants I do a dry fit.  If doing by yourself a practice run may be helpful.  I also tap all the bolt holes for cleaning purposes.  When doing the dry-fit I also run the intake bolts down just to be sure everything is clear and ready to go.  Also a good time to check that all the attachments; vac fittings, brackets, carb accessoriesand  so on .  Point is after you gook everything up you only want to drop the intake on once.  Brian 

[ralt962 11]

I've done it both ways.  The last build I did just the RTV on the ends and its worked just fine.  No leaks.  I use the Black RTV.   This is a 351W in my 69 Mach 1.  

I also use 4 studs (cut off and rounded bolts) to help guide the manifold down to the right spot.  

Agree with dry fit test also.

[barnett468 418]

the gasket can move and even squish out during assembly if you use silicone on both sides. when i use cork i glue it to the block with gaska-cinch then use silicone under the ends and on top.

a silicone bead works xlnt if the right silicone is used. the best to use is permatex ultra gray. it is far better than the permatex ultra black. you may also be able to use toyota fipg but i have never used it for that purpose.

 i sand the gasket sealing surface on the ends of the intake with 180 grit so the silicone can get a better bite on it.

do not put water in the engine or start it until after 24 hours when using silicone only as an end seal.

 

[Rsanter 152]

Rubber end seals are great

better than the cork.

 

one trick I learned over the years is that the cork squeezes out because it grows as you tighten down the intake.

i trim the ends shorter and put a glob of silicone at the end and have never had the cork squeeze out when doing that

 

bob

[Shep69 149]

I’ve just done this on my 302. I had to re torque the bolts about 4 times. Going to check them again tomorrow lol

[Mike65 475]

Thanks for all the info everyone, I installed the manifold today using the rubber end seals. I took 2 old intake bolts & cut the heads off & screwed them a few turns into the heads r/s rear & l/s front to locate the intake easier.