I used them in my HG job last year. So far so good. The engine guy I took my heads to said the cosmetic or gel-Pro would be fine. The Cometic May be overkill, but I was on a redo after leaking oil out of the valve stem seals, and overkill sounded good.

I would use Elring or gel pro and feel confident as well.

 

Overkill sounds fine. When I was 20 I didn't mind skimping because I had time on my side and not money, now I'm short on time and slightly better on money. I don't want to do this twice. I always had a mild interest in this vehicle but I bought it because my wife stopped drinking and turned her life around and has wanted one since the day we met. So here I am. I don't have any desire to do the HG multiple times if I can help it.

 

I still have my 4.6 apart for another rebuild(3 liners leaking coolant after rebuild). I'm going to buy a used 4.0 short block and swap everything over.
This project has been pushed back lately, but still happening(as it's taking up workbench and garage space, lol).
I didn't read comments above yours, but I think I'm in this conversation(or a thread like it).
I was also planning on cometic head gaskets this time. Why? In hopes of a better seal.
Longevity? I don't know.
Why have so few people used cometic head gaskets on these engines? I don't know. I don't know how long they have been available.
I have been considering head gaskets again lately(as I buy parts for my rebuild now), so I was happy to read this post.
I can't disagree with anything you said.
I had also never considered that a failure would happen differently, which is a good point.
These things can have enough heating gremlins as it is.
I look forward to hearing your decision, and how the rebuild turns out.

 

In process.

It doesn't look like the HG is the failure or only failure point. If I put this back together I intend to use the cometic metal HG unless I hear of game changing information in this application.

Unfortunately, I do not see how water would be making it to cylinder 5 which is not next to a water jacket, this is making me point to a cracked head (which would be great as I have a cheap replacement ready) or a sleeve that's leaking which..... would be very sad.

I have used a few blocks of scrap 2x4 wood and the stock bolts to seal up the coolant zones and I believe I can pressurize it using my scuba tank or air compressor and find the leak if there is one. I'm not sure I'll be able to effectively heat the block to make the test accurate with it still in the vehicle but I will have to get creative with some heat guns and see if I can't raise the block temp over 30 minutes or so at which point my test would be more accurate.

I intend to do the test tomorrow. I believe it to be sealed and ready.

 

Yes, reviving an old thread.... Anyone use the Cometic gaskets with success? For me the cost isn't an issue, it is more about durability and longevity. Getting ready to do a HG job with ARP studs and stumbled upon this thread.