Want your guys thoughts for the best thin head gasket for LE2 heads.
Heads are milled .010" and block is decked minimally just enough to clean it up.

I am looking for a CR bump but not at the expense of longevity and reliability.

The candidates are the .029" GM Impala 12553160 gasket and the .026" Mr. Gasket 5716 gasket.

 

my vote goes to cometic gaskets. I am not positive on how thin you can get their gaskets but i know that I personally have never heard a bad thing about them.

 

Did you delete the thread with my reply on it? Ugh.

 

Trying to make a more useful thread.

Your comment was its a PITA to open the Mr. gasket gaskets from the package material, it tends to delaminate the gasket. Putting it in the freezer prior to opening seems to help.

This issue aside I want to focus on the performance and durability of these two gaskets fo my setup.

 

I'm pretty sure this topic has been beat to death. That being said, the freezer really doesn't do much in regards to the packaging, I tried it with two sets, same thing. And if how well the coating holds up to non-sticky plastic is of any indication, I'd rather not run the Mr. Gaskets anyways, they really feel like junk in your hands compared to a quality gasket.

 

You mean these:
http://www.cometic.com/da_viewimage.aspx?da=9

They appear to be .040" thick.

 

I voted the Impala gaskets. They are a little more expensive but well worth it in terms of quality.

 

My vote is for .027 thick cometics.

 

 

When this topic was so-called beat to death I was not needing information. I have searched on each gasket and I get conflicting information which is not enough to make a decision. This post is to directly compare the two gaskets according to my specs that I have provided. This alone makes the thread more unique.

There will always be new information to gain from people who may not have chimed in when it was so-called "beat to death". I am sorry some of you guys feel beat down from repetitive threads, but you were interested enough to open the thread so you either have something productive to add or just to be cynical.

So please provide some productive input if you have some or just visit another thread. Its that simple.

The argument beat to death can be applied to just about any LT1 topic to some extent. This is the best forum with the most knowledgable folks on the net for LT1 information and the term "beat to death", "use the search" etc. etc. etc. as a reply does not add to constructive dialog.

Back on topic, I cant find the .027" thin Cometic gaskets anywhere, anyone have a part number?

 

Functionally, either gasket is probably going to work fine, so its really the thickness that is the difference here. The correct choice for you is going to be whichever gets your quench and DCR closer to you want.

I'm running the 5716 with my setup (same sort of LE2 heads that are milled 0.010) which gave me an 8.6:1 DCR (10.98:1 SCR) and a quench of 0.046. I agree on the whole packaging problem, but i ripped off part of the coating and installed them anyway -- maybe im just lucky but I havent had any issues.

My quench could probably stand to be a little tigher. My DCR is fairly high but it's manageable on 93 octane gas. I have 25k miles on this setup, and the only real CR-related issue was detonation in 1000-2000 rpm while lugging the engine in 6th on the freeway. This was fixed by pulling some timing from the tune.

My advice is to take the time to measure EVERYTHING and figure out the DCR/quench for your planned setup. See which gasket thickness gets you where you want to be.

 

Just got the block back from the machine shop.
The current deck height is 9.018'.

Does this help?

 

With aftermarket rods and pistons, you should have them .018 in the hole. The .026 head gasket will get you to .042 quench, which is good, but not best. You want closer to .035. Good luck without a zero deck. Go with the .026 gasket I guess, even though I already voted for the GM gasket.

 

Cometic will make gaskets how ever thick you want them. I used them on our 386 SBC race motor, and I have a set of .035" gaskets for my LT1. My local machine shop swears by Cometic. They work where they used to have to O-Ring forced induction blocks/heads.

Frank
CPT

 

I got mine from AI and this is from my invoice:
COM-C5645-027 4.040 Bore .027TK LT1 Gasket H1656027S.

Mike