302 intake gaskets

[WaltZ]

which intake gaskets are recommended for a 1969 302 z28...
Thanks in advance!

[67stripper]

I suggest you use these from Paragon or one of the other Corvette suppliers. Link to Paragon is:

https://www.paragoncorvette.com/p-357574-intake-manifold-gasket-kit-all-sb-exc-wfi.aspx

I ordered a couple of sets of these a few years ago and they were cut from a Victor MS15315. A link to Autozone who sells the Victor gasket is:

https://www.autozone.com/external-engine/intake-manifold-gasket/mahle-original-intake-manifold-gasket-ms15315/148219_0_0

You can see in the pictures on the Autozone site that the Victor MS15315 is an EGR gasket. All of the gasket makers and suppliers that I know of only make the EGR type gasket today which looks out of place on the manifolds that do not have EGR. I bought a couple of sets of the Mahle Victor gaskets from a local supplier to check that they were the same as the Paragon gaskets and they had the same part number. Paragon and the Corvette suppliers have the stock Victor gaskets cut to remove the EGR portion. It is not perfect but what is available.

I was not that happy with the Victor gaskets so I bought ten sets of the GM Performance intake gasket 10147994 and had a local gasket shop make a die and stamp out the EGR portion for me. No comparison to the Victor gasket. The GM is a way better quality and consistent thickness.

If you get gaskets that are not the right thickness you will have trouble getting your manifold to fit. The bolt holes will not line up. I've been through all that. One thing you should not do is use any silicone on the side gaskets. This was not available when the engines were make and it sets up too quickly and is too thick so the manifold bolts do not line up.

If you have any further questions don't hesitate to ask. I've researched this extensively and been down the highway.

[WaltZ]

Thank you for this info, I do like the Paragon and ordered them today.

[67stripper]

You are welcome.

One thing you should watch for when using these gaskets is the head side surfaces on the intake manifold. They should be flat. Lots of the manifolds are warped here making them hard to seal. Usually they are high at the exhaust heat cross over because of the heat there. Check it with a good straight edge and if necessary have the surface milled flat by a machine shop that knows how to do this. The surface can be machined with certain types of surfacing machines or in a mill with a good fly cutter. If you go either route make sure you use a machine shop that has done this before and knows what they are doing.

I've had manifolds machined and it really helps with the fit and helps prevent breakage of the bosses for the end bolts which is a common problem.

[janobyte]

Very good point on machining the intake.

[firstgenaddict]

I also used the GM Performance gaskets on the 302 and used a round die cutter to create the "tab".
 - Since then I have found multiple sets of NOS GM intake gaskets from the mid 60's through early 70's and have bought them when they were under $20 a set.
FWIW I found many of the sets of aftermarket gaskets in the 60's are actually GM marked. 

[67stripper]

I've also collected a few sets of older NOS gaskets from various manufacturers over the years. There were a number of changes to the gasket numbers over the years particularly starting in 1968 or 1969 when the 350 debuted with the large journal later block. Sometimes the packages just have different rubber ends seals like for the blocks with holes in the ends for this rubber gasket. For example I have an old GM set package that is 3734115 but the gaskets are stamped 3793290. One could spend some serious time researching this. I believe Detroit Gasket made quite a few of the GM gaskets back in the day. They were proud of their stuff and usually stamped their GM gaskets with DG somewhere.

The one thing I have found with these old NOS gaskets is that they get brittle over time and don't seal all that well. If they swell they also don't fit well and it is hard to align and start the intake bolts. They can also have deteriorating surfaces. That is why I use the new GM Performance gaskets and modify them. GM does not always make great gaskets that fit well for this older stuff but these intake gaskets are just first rate. I have found nothing better.

[169INDY]

Can you go more into detail about the EGR thing,,,,Please & thanks,

Jim

[TODD]

Are you running with the exhaust crossover open? I block mine with a piece of steel sheet. Often wondered why anyone leaves the crossover open. I bend the choke rod to run full open and it looks stock but I don't have 400 degree exhaust heat running under the carb.
Just wondering what others do.

[Kelley W King]

The gaskets in the second link above show a small envelope. They are the SS riser block offs. I use them on my manual trans cars. My L78 automatic I do not. I generally do not use the end rubber gaskets since I have had a couple squeeze out and leak usually at high RPM. Our course my heads could have been surfaced at some time. You can get gasket sealers in orange and silver so you don,t see the blue or black goo.

[67stripper]

169INDY

Here is a photo of a few of the currently available intake gaskets. Top is the Paragon cut gasket made to look like the old gasket before EGR. Second is the Mahle Victor from which the Paragon is cut. Third is the current GM Performance discussed above and last is the blue FelPro that is currently available.

Note that the top Paragon gasket is different from all the others because the profile is before EGR. All of the other three have the imprint in the gasket for the EGR ports. Part of the imprint still remains in the cut Paragon gasket but does not seem to affect sealing.

For an aluminum intake you absolutely do not want to use the current blue FelPro. It is way too hard and slippery to seal well with aluminum intakes. I believe it is marginal for cast intakes. Just a really poor gasket. Unfortunately FelPro has major market share and it can be hard to get other brands from auto parts stores. As I mentioned above, GM is still the best bet. For reference, I have seen Edelbrock instructions for their aluminum intakes that specifically say not to use the Felpro gasket.

[67stripper]

Kelly W King

The package in the photo in the link above is actually silicone sealer for the joint between the rubber end seals and the side gaskets in the corners. Most people don't use this as they use silicone for the end seals rather than the rubber gaskets as you described. This makes sense in most cases as the block and heads have been machined so the distance between the block end wall and the intake manifold can vary quite a bit.

One thing that does happen quite a bit is that the intake surface of the heads is not machined when the deck surface is machined. This creates a mismatch between the intake and the heads and typically the bolt holes don't line up. This is why it is common to see the intake bolt holes to the heads enlarged, sometimes by a lot. If you have heads that have not had the intake surface machined when the deck is machined you can machine the intake to fit. But, this pretty much makes the intake unique to the heads and the block it is machined for. This is also why you can find used intakes that look good but fit really poorly and leak. This is very hard to measure and determine before test fitting on an engine. Buyer beware.

Some intake gasket sets come with the exhaust cross over block off plates and for some manufacturers you have to order gaskets with them which is usually a separate part number. Using stainless sheet instead of the correct block off plates which fit the gaskets they come with can lead to sealing and fitment issues. The tolerances here are actually quite close for good fit and .005 can be the difference between a good fit and a poor fit. As I mentioned above you can really get deep into this is if you want to. Some engine builders really get into this while other just silicone everything together. Matter of preference.

[67stripper]

For those that are interested here is a link to a very good YouTube training video on gaskets with a long time Dana and Mahle employee. This video is from February 2016 and outlines the engine parts and gasket transition changes that happened between Dana Corporation and Mahle when Dana was in financial difficulty. See about 3:30 for the history if you don't want to watch the complete video.

https://www.youtube.com/watch?v=J2C4tqTeXkI

It appears that Dana did not sell the Victor Reinz brand of gaskets to Mahle like the Clevitte and Perfect Circle brands and took back the gasket brand in 2016. As a result Mahle and Victor can be quite different gaskets. I'm not sure what is happening now but when I wanted gaskets from Mahle a few years ago they were in short supply. However, it looks like Victor is up and running now after they took back the brand from Mahle. Watch the video if this interests you.

[firstgenaddict]

I almost always look through sets of older gaskets at swap meets for the correct intake gaskets.... many guys have NORS sets of Victor gaskets for sale at Charlotte, Carlisle, and other large meets.