I have a blown head gasket(s) and need to replace them. My LT1 heads were already shaved down twice, so what thickness MLS head gaskets should I get?

I have a forged 355 with 10.2 to 1 comp and 12 pound vortech supercharger.

I appreciate the help!

 

Sleeper,

What gaskets were you running?

Felpro 1074's are pretty common and seem to work ok for most. I think the compressed thickness is like 0.039". You do have a lot of static compression for 12 psi.

Are you looking for a thicker gasket? I could be wrong but, but does Cometic offer a gasket thicker than 0.040"?

http://www.cometic.com/domesticauto.aspx

You're probally getting into some detonation if a 1074 or the like is letting go. Be careful.

-Scott.

 

I'm not sure yet I'm working on getting that info from the last guy who replaced them. Yes, I need thicker but I don't know how much thicker, just enough to prevent it from blowing out again. And I definitely need lower compression.

Are the Felpro 1074's multi-layer steel?

The thickest MLS cometics are .140. I forgot to ask if they were for an LT1 but I happen to know that the C5895-030 are for LT1 and he told me those are .030

 

Do you know why the head gasket failed? While a thicker head gasket will help to lower your compression ratio a small amount, a thicker head gasket in itself won't necessarily stop the problem from occuring again. Cometic gaskets are good quality, but require a specific "finish" on the head and deck to ensure proper sealing. Felpro 1074 gaskets are not multi-layer, but are considered one of the better choices for boosted LT-1 applications. It may be better to have a "fuse" in your system (the head gasket in this case) that fails before internal parts start to break as a "blown" head gasket is usually a sign of a bigger problem such as detonation. You may want to consider a set of aftermarket heads since they will give you the ability of selecting the correct combustion chamber size in order the obtain the desired CR, not to mention they will ultimately flow better than your stock heads.