It's a problem that I've been working on for the last year, and seriously for the last 6 months.
In the interim, until a suitable replacement is available, head gaskets are still available from Kurt White. His website lists;
81 ea 10106177 LH Head Gaskets in stock @ $98.16ea
10 ea 10106176 RH Head Gaskets in stock @ NOT SOLD SEPARATELY, SETS RH & LH ONLY.
Interestingly enough, he indicates the shortage is with the RH head gasket. My experience and that of others has been just the opposite.
As a progress report of sorts: In my research, I've found that the term open deck includes several different concepts, ranging from the LT5 design at one end to designs like the new Chrysler/Dodge engine presently used in NASCAR. The Dodge engine has the cylinder bank cast into the block & is not replaceable. It's open deck, but a cast-in, integral part of the block casting. Head gasket development for an open deck engine of this type is not a problem.
The LT5 engine is a miracle in manufacturing perfection of precision machine work with exacting tolerances, but it presents some problems in being able to verify the flatness of the head gasket deck surface of the individual cylinders as an assembly within the cylinder case from one end to the other and across the block deck. For MLS (multi-layer steel) gaskets, it creates a problem in that Cometic has stated to me, "the MLS head gasket will leak if flatness is over 0.002". Not maybe but will. This is not to say that it can't be achieved, but it's going to require some special tooling and significant skills to be able to check flatness of the cylinder/block considering the cylinders should have a 0.002" ~ 0/003" pride heifght above the block deck.
This issue begs the question about how the stock head gasket achieved the seal. I can only offer my opinion based on knowledge gained during research, but it is by no means represented as "the final answer." The stock gasket is made from a polymer named "Astadur." Its pliable in its new state, but hardens during the heat cycle of the engine during operation. This flexibility permits the gasket to compensate for the tolerance of variance normally incurred in manufacturing and assembly of the LT5 engine, by letting each individual cylinder's combustion seal align to the cylinder deck. Once the gasket hardens, it provides more backing support by becoming stiff & rigid.
The problem with MLS is that they don't have this flexibility and may not have the ability to conform to each individual cylinder deck. Bottm line is I think it's a crap shoot with MLS in the LT5. Maybe you get a seal on all 8 cylinders and maybe you don't. It's a real gamble to take on a headgasket considering engine removal and cam timing. The MLS gasket's greates attribute, rigidity/strength, is its biggest liability for the LT5.
Is Astadur available. In short, no. The gaskets were originally made by Goetze for GM. Goetze has since been acquired by FelPro. FelPro has not returned any of my many calls and emails.
Are there other possibilities for stock replacement? I certainly hope so, but it's not coming easy.
What about the cost for stock replacements? In excess of $300/set.
What about high performance buid solutions (12:1 plus and boosted engines). Also on the board. Certainly expensive, requiring new cylinders/liners/sleeves, but much better than conventional style head gaskets, including Cometic MLS. Pricing & details not ready for publication.
In summary, I'm willing to invest a significant chunk of change to develop a replacement head gasket for the LT5 engine. I'm not willing to do it for a product I don't have confidence in that it will do the job at least as well as the original head gasket. Getting that confidence is the really difficult part. One engine build doesn't guarantee success, but it does require the total investment into up-front tooling & manufacturing costs. Before I do it, I will have to be convinced of a very high degree of certainty.
.....and that's the way it is. Good day
