I have a 1998 Ls1 engine that has the 806 heads in it now.
Im getting ready to install my newly CNC'd 243 Heads, what gaskets do i need to use? the 98 graphite style or the new ls6 ones??

thx

 

ls6 mls

 

GM updated them for a reason, and if/when you pull heads wong be near as hard to clean up I bough GM mls for like 36$? IIRC from Scoggin Dickey

 

Looks like this pn right here for 02 and up
http://www.sdparts.com/product/12498...2002andUp.aspx

this pn here for 97-01
http://www.sdparts.com/product/12498...GasketKit.aspx

your 243s should be the newer gasket style...the 12498544
that is for a complete set of head gaskets. then of course you will need the hea bolts, valve cover gaskets and any necessary intake/air/egr gaskets.
we have those in kits as well, just let me know what you need and ill get you set up.

 

I have all of the other stuff already.

So....with the 98 style ls1 block what gasket should i use with the 243 head?

If the difference between the PN you listed for graphite and non and thickness?

 

difference is in the head not the block. the 98-01 heads have a notch in them that will leak water if the right gasket is not used. Your heads (if they are actual 243s) will not have that and they can use the newer gasket.

 

John, on the listing above for newer style GM MLS it shows the compressed thickness approx. .060. Is that correct? I see most using .051 or .053. Please clarify if you can!

 

That is the measurement we had originally measured when those parts came out. We only use GM spec if they match with our spec. But those parts are diff in the fact that the 8543 is graphite and left/right and the 8544 is MLS steel and universal.

We are measuring them right now to see if GM has changed the design to publish a .051/.053 for all of them.

Ill let you know in a little bit.

 

I see, yes they are 243 Castings.

But I can use either gasket and be fine...correct

What gastket is better suted for abuse?

I also saw that thinkness difference also.

 

Jury is in....
8543 graphite will be .051 when compressed

BUT
8544 looks more like .057 to .059 when compressed.

These are brand new gasket kits, they just came in the other day.

Ill change the specs on the site.

 

Thanks John....now I don't know what to do! I had calculated 11 to 1 compression with my TFS 215's milled to 61cc and GM MLS gasket at .051-.053 on my 03 Z06. Guess I will have to recalculate and see what it is or use Cometics which I was trying to avoid due to leak issues!

 

Leak issues on cometic? have not heard of any beyond a very high HP boosted app pushing water.

 

All kinds of posts on here about leaks after install. May be from owners fault not getting block clean though. Lots of guys are using copper spray as a precaution even though I have read Cometic doesn't recommend it. If you search you can read a bunch!!

 

On tech doesnt mean the entire LSx universe. I have sold so many sets i cannot count and i have heard of no issues short of intallation error for them leaking. Remember, the house is only as good as the foundation it is built on.

 

Ok, can you give me a link to Cometics for my TFS 215 heads in either .40 or .045? I guess I need to order some!

 

what notch are you referring to? where? what does it look like? I don't ever remember ever being told about that. I have a set of 241s and I was losing coolant into the oil. May have been just a blown gasket, but you never know.

 

what bore size?

the 241s should not have the notch. They are on the outside edge between the bolt holes on the outside right at the corner of where the deck surface comes up to teh exhuast manifold port side. the graphite gaskets are designed with a silicon printoseal to keep from leaking. The other gaskets are not and will leak.

 

I can't seem to navigate that site to well. I can't find lsx bases head gaskets on there to save my life. What part number am I looking at for a 4.030" motor and something in the .050-.060" thickness?

 

cometics here.. with arp head bolts 90* past final.

sealed great... and I beat on it

 

part # would be an SDL403050 or 51 or SDL403060 if you phone it in. we do not have those part numbers up on our site at the moment. They are 72.95 a piece.