All right I have searched and searched and searched no anwsers to my question. Im gonna be swapping 799s on my 2000 5.3 I know there is a numb or something on the block what head gasket can I use 99-2000 or 2002-07 Im asking before I start with this swap. Or is this little numb gonna be a biggest pain in the world. Has anybody here swap 799s to 99-2000 5.3. Thanks for the info

 

IIRC, the early heads have a notch that won't allow them to seal with the newer MLS gaskets. So with the earlier heads, you've got to use the composition gaskets.

Since you're installing the newer 799 castings, you should be okay with the MLS gaskets.

Here's a pic of the "notch".

 

Look into GM part number 12498544. It's a "kit" that has both head gaskets, for a very good price. They are MLS.

 

Ok so the notch is on the head not the block that's good news and using 99-00 gaskets is what I'm gonna need thanks guys

 

No, don't use the 99-00 gaskets. They are composition, not MLS. I guess either will work, but I believe the MLS gaskets are better. The part number I listed is MLS and should work with your new heads.

Are you using ARP bolts? You'll need the bolts for the earlier blocks, with the long & short bolts.

 

Yes will be using arp bolts that came with the heads I got I will check to see if reusable or not

 

Newer heads as Roger said you can use the MLS gaskets, but with the older heads like the ones pictured with the notches, you need to use the gasket for them, not the MLS style one.

 

Everything above lol

Im running a 98 ls1 block that had the notched heads on it and used GM MLS gaskets when i put the 243's on with no problems

 

Alright did call arp and can reuse there bolts and gonna order the mls gaskets anything else you guys can think of I'm gonna put ls7 lifters double roller timing chain ls6 oil pump just need a tbss intake and a cam

 

Pretty sure those 799 heads will have come off a 2005 or newer engine. The ARP bolts for the newer engines won't work on your older block. The lengths are wrong.