ws.6kid

I read on a website that I can not use MLS gaskets on 98 LS1 Heads.

"These early heads are unique because they had a recessed area right below the No. 3 or No. 6 cylinder, so rebuilders must use the early style, composition head gaskets with them. If the later MLS gaskets are installed with the heads that have the recess, the engine will leak coolant to the outside from the recessed area in the deck surface."

I dont know how old this is, but does anyone make MLS gaskets that work with 98 heads? If not then what gasket should with hold with a H/C 347 with a 250 shot? I plan on running ARP head studs.

Reckless

iTrader: (9)

That is correct. You want to use the gasket for that year model heads. If you look at the heads, they are notched out along the lower edge of the head and if you use the GM MLS gaskets they will not seal there and you will leak coolant.

You can however use an aftermarket MLS gasket such as the Cometic I believe.

ws.6kid

Um so any aftermarket MLS gasket will work just not the GM one?

ArcticZ28

iTrader: (14)

If you're going to go with MLS, go with Cometics and spray each side with copper spray sealant. That will seal up any small imperfections that may cause leakage.

777

iTrader: (21)

Like said above. Find a gasket that is compatable with your model year. They will tell you if they will work or not.

I thought they were supposed to be used dry?

ArcticZ28

iTrader: (14)

It's been debated. I personally decided to go the route of taking every step to ensure no leaks and I have had no problems. It just wasn't worth the risk of putting them on and having them leak (from some small difference in the heads) when I could have just used copper sealant from the get-go.

777

iTrader: (21)

I see, why would they say to apply them dry. Is there some possible problem when spraying them with the copper sealant?

Demon SS

iTrader: (3)

the issue in question is not a small imperfection, it is a "notch" that is part of the casting, while copper sealant might work, if would be iffy.
the MLS gaskets should not be used for the reason stated above, we cure the whole issue by welding up the notch and then milling the head, end up only doing a slight resurface of like .002

ArcticZ28

iTrader: (14)

Yea, that's why I said "if" he was going to use them. I personally wouldn't b/c of the notch size, but I used them on my LQ9 heads.

strokedls1

iTrader: (1)

Yah you need to weld and resurface the deck. Then you can use a 98 specific head gasket. My friends 98 is where cometic learned the design issue of differences in the head from 99+. Cheaper and easier to just use a stock gasket unless your looking for the extra compression and quench from a mls.

ws.6kid

Well my whole issue is being able to spray a 250 shot, I figured stock head gaskets would not cut it, even with arp head studs. What gasket is safe to run with a 250 shot on top of 450 rwhp??

bigdsz

iTrader: (1)

The OEM MLS gasket is .060, and the OEM graphite is.054. Consequently compression and quench is slightly better with the graphites.

ArcticZ28

iTrader: (14)

I personally would only trust Cometics for that sort of application. And to play it safe, spray each side with the copper sealant. That is definitely your best bet.