DriveATransAm

whats the difference between 98 and 99 head gaskets? i thought the heads were 98 but they are 99s. will 98 stock graphite head gaskets work with 99 heads basically?

Ryan02SS

iTrader: (3)

I've talked with a few shops about this and the general consensus is that grpahite gaskets were OEM used from 98-01 on the Fbody LS1's. In 02 and some even say late 01 models got the new MLS gaskets.

DriveATransAm

are they the same gasket though? i thought they were different?

DriveATransAm

ttt??

DriveATransAm

ok nm. i called the dealer. he said the part numbers for the gaskets are all the same from 97 to 2001

PREDATOR-Z

Check on the gasket if they have a lower notch.

https://ls1tech.com/forums/attachmen...chmentid=35007

That is a 99 head (853 casting). MLS Gaskets for that head need a notch.

2xLS1

iTrader: (25)

Actually, I took that pic and it is of a head off of my 99, casting #853. Any 853 casting will have the notch and they were used through 00 MY. The GM graphite gasket will not have a notch there. The problem is if you use the 02+ GM MLS gasket with heads with the notch, it will leak coolant there. The graphite gasket seals around that notch and the GM MLS does not.

PREDATOR-Z

Ok I edited.
Doesn't the 97-98 perimiter bolt head have that too?

2xLS1

iTrader: (25)

I think so, but I havn't seen a set off the car. I thought all pre 241 heads have it.

Zick

iTrader: (18)

My 98' has those notches on it.

PREDATOR-Z

which means 97 have them too.
So 97/98/99/00 have those notches, Graphite will seal them fine but MLS gaskets have to be specific to the year (unless the notches have been welded)
That sums it up.

2xLS1

iTrader: (25)

My 00 has 853 heads too.

ssheets

iTrader: (1)

Is it true that you can use the graphite on either, but you can only use MLS on the non notched heads?

Also graphite are .055" and the MLS are .060"

2xLS1

iTrader: (25)

Even the 01 cars with the 241 heads (no notch) used the graphites so your first statement is correct. Also graphites have a separate L&R part. MLS can be used on either side, same part. I'm not up on the compressed thickness so I'll let someone else answer that.

PREDATOR-Z

.053 compressed for the graphite (measured)

ssheets

iTrader: (1)

I've heard any where from .054" to .056" ..I like your .053" better
I'll be using the Graphites on 5.3 heads, with a compressed hieght of 0.053" a chamber volume of 59.25 will give me 11:1CR not sure if I can quite get there, but I should be close.

PREDATOR-Z

You will be there.

http://www.c5frc.com/calculators/Com...Calculator.htm

oange ss

iTrader: (50)

the GM MLS are .051 compressed right ? what would you recommend for a head swap ? Cometic or stock GM ? what would quench be for stock bore, 5.3 heads with 62 cc and MLS gaskets ? thanx


sorry, these questions were aimed at Predator Z

PREDATOR-Z

GM MLS are thicker than graphite. .060 compressed. Not good for quench purposes.
Cometics are the good ones but good luck finding any in stock (3>4 week backup order)

oange ss

iTrader: (50)

what gaskets would be good for quench ? dont wanna go to small to help keep compression down, thanx