@LoxDiesel : I have both the fel pro and Cometic head gaskets in my shop right now. Measuring the thickness of both at the cylinder compression area: FelPro = .081" thick , Cometic = .087" thick. Measured with calipers and compressing the layers without crushing, as best as I could. Thats a pretty big difference. There seems to be more meat at the high pressure ring, which only makes sense and confirming their claims. I also like the fact that the entire top and bottom surface is coated versus just around the openings like all the other gaskets on the market.
With these facts in mind and and your 30 truck history, I'm going with the Cometic head gaskets.
What torque settings are you using on the ARP studs to set the heads?
First off let me say that I have no idea which gasket will hold up better when it comes to the Felpro vs. the Cometic. I will say that the thickness of the compression ring and the area that is coated has a lot less to do with the "Strength" than the actual steel(s) that each layer is made out of and the type of coating that each manufacturer is using. But, unless you are the engineer who designed the gasket and knows all of the actual data...it's just a guessing came, and that's about the best you can do.
As far as the ARP head bolt torque goes....I would follow the instructions of the people who did the R&D on them, and manufactured them...ARP. ARP says torque to 90ft/lbs, then 180 ft/lbs, and then a final torque of 265 ft/lbs.....and make sure you use their special ARP lube when you do it. When it comes to that stuff....there is only one right way to do it, the way ARP says to.
Good luck, I hope those Cometic gaskets work good for you. Check back after and while and let everyone know! :smile2:
My instructions say to torque to 210 fllbs. They lowered the torque spec on the most recent ARP studs because of the ultra torque lube ,that comes with them, is supposed to be better and you lose less torsional friction as a result of using the more slippery lube, so they say. I'm on the side of going a little bit more. Mine are all at 210 right now. I'll probably go back around and hit them one more time at 225 ftlbs, because, why not! @LoxDiesel, Thanks for your help so far.you're quoting the torque for the ARP 625's. The regular 250-4202's are recommended to go to 210 ftlbs. HOWEVER I've been studding these engines since 2008. When I first started using the ARP's the torque went to 240ftlbs. So I never stopped doing it that way... Haven't had a failure yet...
I had a piece of the screen break loose two years ago. It prevented the valve from closing completely. couldn't get enough oil pressure to run the injectors. That is when I replaced the HPOP T fitting, tubes and dummy plugs, blue spring and a couple other preventative upgrades. Rebuilt the turbo also while it was off.I had a leaf end up covering 1/3 of my IPR screen causing all sorts of chaos.