I need an experienced opinion on whether to use Hylomar Universal Blue or Gasgacinch to seal the valve cover gaskets on a 440 Chrysler engine. Heads are aluminum Eelbrock performer and I will be using cast aluminum valve covers. I'm planning on using a Fel-Pro rubber "Fel-Co-Prene" VS 13379 R valve cover gaskets. I also have some Fel-Pro Cork valve cover gaskets on the shelf.

I have both Hylomar Universal blue and Gasgacinch on my shelf, but have never used either for valve covers. I have used Hylomar on a thermostat housing gasket which worked great. I have heard good things about Hylomar and Gasgacinch so I bought both, but wonder if one works better than the other for my application. I do not want to use any RTV sealant such as Permatex Ultra Grey, as it did not work previously, still leaked oil between the gasket and the head, eventually dripping oil out on to the headers. Engine has a solid lifter cam, so the valve lash needs to be checked occasionally. I also hate removing the residual RTV from the heads and valve covers.

Leak free valve covers is my goal. Thanks!

If you want to use a good gasket adhesive Gas A Cinch, it is your friend
If your wanting to seal the gaskets up so they won't wick oil through them use Hylomar. BTW, I do use Gasket A Cinch as a gasket sealer on all sides on all my cork valve cover gaskets
Do your cast aluminum valve covers have a flat sealing surface where the gaskets mate to or do they have a raised ridge in the center of the sealing surface? If flat your good, if with a raised ridge I have seen them split the valve cover gaskets in half with multiple reuses
I'm going to have those ridges removed and make the sealing surface flat from now on

Thanks Cab. My cast aluminum valve covers have a flat machined sealing surface. I definitely want to seal the gaskets so they won't wick oil through. I have seen fires from oil leaking out of valve covers on to headers. I want to do my best to prevent the mess and danger of oil leaking from the valve covers. Would you use the rubber gaskets with hylomar or cork with gasgacinch on my engine application?

Are your "cork" gasket pure cork or a cork and rubber mix? If mix use them, don't over tighten them when installing them Go back and retighten several times as needed after you start driving the motor I don't remember the factory torque specs. on the 1/4 inch rocker arm cover bolts or nuts, but it is not much I use snug them until the cover just touches the gasket and use another 1/8 to 1/4 turn tighter max after that

I have a set of Fel-Pro 1611 valve cover blue stripe cork-rubber gaskets. I also have a set of Fel-Pro "Fel-Co-Prene" VS 13379 R (black rubber) valve cover gaskets

https://www.summitracing.com/parts/fel-1611

"Blue Stripe® cork-rubber combines the qualities of cork and rubber gaskets. It maintains its shape and flexibility, yet is highly compressible. It seals well because of its good compressibility and is easier to install than synthetic rubber gaskets because cork-rubber is somewhat rigid."

So you would recommend as #1 using the Fel-Pro blue stripe cork-rubber valve cover gaskets with Gasgacinch? How would this compare to using the black rubber gaskets with Hylomar?

Since both surfaces are machined I don't use any thing with the gaskets.

I Agree

Also make sure your bolts are not to long , bottom out in heads and not sealing , or are you using studs ?

And third

Superformance Carbon X Valve Cover Gaskets

Gasgacinch them to the valve covers, then a thin film of Vasoline on the head surface, don't overtighten to the point of splitting the gasket. That seal will last many years with repeated removal/installs. my

Thanks for the suggestions. Seems more have used Gasgacinch. Any experience using Hylomar with cork or rubber gaskets on valve covers?

I'll check the bolt length to make sure they are not bottoming out.

Superformance gaskets siliconed to the valve covers and dry on heads has worked for 6+ years for me on the same original set I got from Greg.......

The rubber coated steel gaskets do not require any sort of sealer. I'm running the gaskets from Cometic. They are much more durable than the soft rubber ones that Moroso make but they are also more expensive.

Thanks Andy! I was not aware that Cometic was making these valve cover gaskets. Just ordered a set from Summit. I want to give these a try.

I have a set of the rubber/steel moroso gaskets on my edelbrock heads with an old set of cal-custom cast valve covers and they don't leak a drop and no sealer required.

I'm very happy with em, had em off several times over the last few years and they're still like new.

I agree that with my aluminum heads and aluminum style valve covers that both have nice flat surfaces I dont use any sealer and it works good without any leaks. I have used the SuperPerformance gaskets and the blue Moroso gaskets you see here with good results and no leaks. Ron

I have come to depend on Permatex Aviation Form-A-Gasket for anything thats going to see oil. I run stock valve covers on aluminum heads and have found good success with the Fel-Pro rubber gaskets glued with the above referenced stuff into the valve covers, then onto the heads with no adhesive at the bottom sides of the gaskets.

Update: I purchased a set of Cometic valve cover gaskets and installed last week. I started my engine today, and guess what, NO LEAKS!!!! Also very awesome to not use any RTV on the valve covers. I would definitely recommend everyone giving these a try. Thanks Andy F!

https://www.summitracing.com/parts/cgt-c5983/overview/

Thanks for the feedback/update. sometimes you never know what the outcome was on here.

Glad they worked for you. It really depends on how well the cast valve cover is made. If the rail is in the correct location and is smooth and flat then the gasket has a better chance of sealing. We just finished doing a bunch of rocker arm tests so the valve covers were on and off a bunch of times. No leaks with the Cometic gaskets and no problems re-using them over and over.