Tiago

iTrader: (27)

My motor is about to be reasembled and I started getting worried about the "notch" on some heads. On a previous thread someone told me the 99s didn't have a notch. Look at these pics...




If you look you can see the a "notch" on the edge of them. I hope this is not the famous "notch" or I will have a problem. I bought the GM 6L MLS gaskets.

the head casting number if Im not mistaken is 853.

So am I gonna have a nasty surprise running this combo?

Scalpel

iTrader: (4)

GM MLS gaskets won't work with those. You'll need the graphite gaskets. That is the infamous notch.

Tiago

iTrader: (27)

xssive

iTrader: (123)

Yessir thats the notch...

SuperSporttruck

iTrader: (2)

what is that notch for and why do you have to use a different head gasket ??

S_J_H

Just run Cometic or Mr Gasket MLS . I run Mr. Gasket MLS on my notched 98 heads without issue.

Steve

RICE ETR

iTrader: (3)

It stinks you already had them milled.... but you can get that notch TIG welded up, the heads milled and then you can run the cheaper gaskets. I know of a few people on here who have done this.

Scalpel

iTrader: (4)

Just an aside, but holy **** you have a LOT of parts scattered around. It looks like an FI setup blew up in your garage

Tiago

iTrader: (27)

ahaha, essentially that is what happened....

yea too bad they are already milled, now I gues I will run stock graphite gaskets until later on when I swap heads then I'll run the MLS...

Lostpatrolman

iTrader: (3)

where is the notch, and why is it a problem?

Phate

iTrader: (2)

I had the notch in my heads welded and used the MLS gaskets. Worked fine.

NA$TY-TA

iTrader: (21)

This is why they are a problem.................



Its the weakest part of the head and block..... blew a headgasket and took a junk of both with it.

Kyle

MIGHTYMOUSE

iTrader: (59)

if you can stand to loose another .007 off the heads you can still get it done for those.

sjh how much and where to get the mr gasket mls?

the cometic c5475 is what i am still using but they are expensive and hard as crap to find.

Tiago

iTrader: (27)

well my reasoning is that with the current heads I won't regularly see more then maybe 650 rwhp on pump gas due to compression ratio, maybe closer to 600 rwhp. So I am just gonna run graphite stock gaskets till I swap to new heads.

1point3liter

Everyone else has pointed out the obvious.

But for the record, 99's definately have the notch. I had 99 heads.

S_J_H

NA$TY-TA, I'm not so sure the notch had much effect in that damage. You have coolant passages closer to the chamber than the notch in both block and heads which are weaker areas. I have flame cut notches like that in both block and heads in other motors of mine. Just your typical poweradder damage when things go wrong. But that notch is a pretty stupid thing to have put on the head deck and certainly does no good of any kind.

MIGHTYMOUSE,
I got mine from Summit racing for 66$ each.They look just like cometics to me. I coated mine with hi temp aluminum paint also.
Here's a link- http://store.summitracing.com/defaul...umber&x=15&y=7

1point3liter

sjh,

Those have a compressed thickness of .040 and a 4.130 bore?

MIGHTYMOUSE

iTrader: (59)

wish ida seen that 5 days ago.. ah well..

im wondering how well the 6.0 gaskets and those 4.13's press onto stock cid's steel sleeve? i would think it would only be right on the outside edge... and that would not be as strong as the cometics wich are stock bore

S_J_H

yes, 4.13 bore but that is a misprint on the thickness. They are stock .058" thick.

I'm using them on a 3.905" bore with my heads opened up to 73cc with a 4" chamber bore.
They are situated on the sleeve deck no problem.
I have had them to 15psi a few times and have had them on a full year now.
Steve