Best headgasket?

Cometics x2 ... just remember that head gaskets are your engines 'safety fuse' against detonation damage. Using metal gaskets that will take more abuse make make the damage appear elsewhere.
 
From past experience, your block should be machined to a 90RA with Cometic Multi-layer gaskets, which is very smooth. The GN1 heads usually have the correct finish from Champion. You can run them without the block being machined, but they could leak or suck coolant. In any case, use GM/AC Delco stop leak tablets with Cometics.
 
I've done 3 jobs with Cometics on stock finished motors, no leaks. Make sure everything is super clean and use copper spray on the gaskets, also used a small amount of RTV around coolant passages.
 
I know a shop that drills out the rivets and coats all layers with copper spray. RTV around the coolant passages sounds like a good idea too. Cometic says not to use anything on the gaskets, but they are assuming a perfect surface.
 
From past experience, your block should be machined to a 90RA with Cometic Multi-layer gaskets, which is very smooth. The GN1 heads usually have the correct finish from Champion. You can run them without the block being machined, but they could leak or suck coolant. In any case, use GM/AC Delco stop leak tablets with Cometics.

What is a stop leak tablet and how is it used/applied?
 

Spray the entire surfaces of the gaskets with Copper Coat thats when using the cometics. They are a mutli layer headgasket and have rivots holding the layers together. They seal the combustion great but have a tendency to seep oil and coolant. So by spraying the copper coat it helps to ward off the seepage. Thats why the mention of the GM seal tabs and rtv around the water jacket/coolant ports on the headgaskets.

I for one do NOT like using seal tabs as it makes the coolant look horrible and you have all that fiberous junk in the cooling system and you cant tell if you have rust, etc in your system.

I dont use copper coat with the felpro 9441 since they have a tacky finish on them out of the package. Key with the felpros is to not handle the surfaces and mess up the tackiness with dirt/grime and finger prints.

IMO max effort really leaning on the car 26 plus psi very frequently run cometics otherwise use the Felpros.

With any headgasket its ultra imporant to wipe down mating surfaces with a good cleaner that doesnt leave a residue when it flashes off. I like acetone and keep wiping it down with light colored lint free rags until they come clean.

And dont detonate with any headgasket.
 
Agree about the sealing surface being clean! Appreciate the more detailed information on the use of Copper-spray on Cometics as well.

My current setup calls for 31PSI with my TE60 but with the 6266 CEA and this motor probably closer to 24-25PSI.
 
Is that with a chip cause its gonna be way rich with 2 different turbos and that far apart on boost. Turbos are considerably different
 
I have used the AC Delco 10-108 seal tabs and only use 3 or 4 tabs with Delco long life coolant. I do not see any residue in the cooling system like with other stop leaks.
 
I have used the gm seal tabs for years in many vehicles.

These are a vegetable based seal tab that seem to work very well

They can make the radiator look a little dirty but only when running straight water which is the only thing I run in my non daily drivers.

I use the cometics and have had nothing but good luck. I have used the copper spray but prefer hylomar although I have not seen it available in a few years.

You must ensure that the surfaces are perfectly clean, I use virgin laquer thinner, wax and grease remover and lint free wipes all which I purchase from my local body shop supply center.

Follwo the recommende3d torque sequences and specs and I have never had had a leaky cometic.

Now this new engine I am changing it up a bit and using the SCE coppers but the heads I bought from weber had a wire in the head. Hopefully this combo works.

If not back to the board im just adventurous in that way
 
I am about to install the one's from RJC on mine. Was running felpro.
I have a forged Weber shortblock with aluminum heads.I want to go with 0.032 RJC head gaskets or 84/85 GM steel shim head gaskets.I assume that an OE deck surface texture is correct given thats what I used when I ran 84/85 steel shims and they were great.Any other knowledge would be awesome.Thanks for looking.
 
i am hearing some are switching to copper gaskets for high boost motors, whats the advantage/difference compared to cometics?, also do you need or is recommended to o ring the head/and or block, who is a fan of copper over others? any long term users out there? have heard bison may be a fan of these? more info here would be great, we all learn alot from these threads, ??
 
I'm pro Cometics but something I believe you should know is if something goes wrong and you end up blowing one they tend to take a chunk of aluminum head with them, not a problem with iron heads...so I do believe you should at least consider a head gasket that might not hold up to quite as much detonation but a head gasket change is easier than getting a head repaired or replaced.
 
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