Crackheadjoe

Hello guys I'm new to the forum so here we go !!! So I'm putting twin turbos on my 5.3 lm7 gen3 next mind you I'm not building this to go race its just a weekend truck amd move of a conversation peace all stock but it has a mild cam with 862 heads I'm not gonna run over 8psi I want the truck to last as long as possible I'm putting APR STUDS when I put the heads back on this guy at summit racing told to run this heads gasket which thinner than stock not but that will raise the compression up a Lil???? Which it is bad but with low boost will it be fine ???? Is my question

gnx7

iTrader: (28)

BTR sells their own brand (same company that makes them for GM) small bore LS9 head gaskets and PointOne head bolts/studs. You should check those out also.

You should also confirm what rods are in it. Sometimes the engines closer to 2004 production year have the Gen4 rods inside.
https://sites.google.com/site/sloppy...3-or-gen4-rods

LS1Formulation

iTrader: (13)

I just got a pair of those small bore LS9 gaskets, they're nice. I wouldn't run the Fel-Pros with a turbo combo.

slowride

iTrader: (3)

Well first off do the heads have the notch in the deck like the earlier ones can have? If not you can run the smaller bore gaskets or just the simple ls1 5.7 gaskets no problem. If they have the notch it limits you to certain gaskets. Mahle and a few others make a consolidated gasket that will seal on the notched heads.

Forcefed86

iTrader: (4)

862's don't have the notch that I'm aware of? pretty sure that's only the parameter LS1 stuff 806 & 853.

Anything over stock is overkill for 8lbs. You literally need nothing to run that kind of boost. Don't over complicate it. Any factory gasket with any factory fastener will do and have a long service life. spendy studs/gaskets aren't going to do anything but hurt your wallet.

slowride

iTrader: (3)

706 and 862 can both have the notch also, but maybe not as common?

Forcefed86

iTrader: (4)

Not saying that isn't true, I've just never seen or heard of that. Where do you get that info from?

slowride

iTrader: (3)

I’ve seen them in person at the machine shop I used. I think it’s older engines as it seems all notches went away around 2000-2001 no matter the application so it would only apply to the earliest 4.8/5.3 stuff. Now I’ve followed ls1/6’s the most back in the day where both of my friends had 99’s frc vettes with 853’s and center bolt valve covers with head notches also

5.7stroker

iTrader: (36)

So say the bore of the block is 4.005 after the cylinders are cleaned up. Does it matter if a 4.040 gasket or a 4.100 gasket is ran? With a 4.030 bore I'm assuming a 4.100 gasket is the go to.
Boosted application, 20-25 lbs.
823 heads on a gen 4 iron block

Does a Cometic MLX seal any better than a GM LS9/BTR LS9 gasket?

Cometic MLX GM LS Gen-3/4 Small Block V8 .032" MLX Cylinder Head Gasket, 4.150" Bore .032, .040, .052 (C5014-032, C5014-040,C5014-052)

Cometic MLX RHS GM LS9/LSA Gen-4 Small Block V8 .040" MLX Cylinder Head Gasket, 4.100" Bore .040, .044, .051, .052 (C5985-040, C5985-044, C5985-051, C5985-052)
Cometic MLX LHS GM LS9/LSA Gen-4 Small Block V8 .040" MLX Cylinder Head Gasket, 4.100" Bore .040, .044, .051, .052 (C5986-040, C5986-044, C5986-051, C5986-052)

Cometic MLX GM LS9/LSA Gen-4 Small Block V8 .040" MLX Cylinder Head Gasket, 4.040" Bore .040, .044, .051, .052 (C5505-040, C5505-044, C5505-051)

GM LS9 12622033 4.100" Bore .055 thickness
BTR LS9 - LIKE 12622033 4.100" Bore .055 thickness (cheaper that the above, told it's the same exact gasket)

Why are the Cometic LS9 gaskets different from L and R sides but the GM LS9 gasket is the same part number for both left and right?