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Discussion Starter #1 (Edited)
I have an L33 which is the aluminum 5.3 LS.
I used the GM std 5.7/5.3 3 layer MLS gaskets. Studs torqued to 75 ft lbs. Yes, the cheap studs.

I wasn't paying attention to the coolant overflow and have been pushing waster from the get go. Once I noticed, I paid attention, thinking maybe the cooling system was trying to find it's happy level.

The happy level turned out to be empty.....

Took it apart, and cyl 8 had lost the seal between the gasket and the head pressurizing the cooling system.

I did get this into detonation in early tuning sessions. But only once.

Also had my heads surfaced, and my guy has older equipment and the finish was rather course. No clue what it would measure on the RA scale. So I think I had two issues contributing.

I will have the heads resurfaced by another shop who can get them very smooth.

I don't wish to do this again, so what gasket are you "go fast" guys running?

Cometic doesn't seem to make a 5.3 specific gasket.
Fel Pro does in MLS, but it's not in the performance line. I've heard it works well though?
The perf Fel Pro is for a 5.7 bore. Maybe not an issue?

I know a lot of folks use the GM LS9 gaskets but that is for a 4.1" bore, way bigger than the 3.8" bore, and it just doesn't make sense to me. Even if it works......

Looking for suggestions.

BTW, E85, 15psi. Have not seen a bit of knock retard since early on.

Thanks

Ron
 

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what you said makes no sense whatsoever. you dont want to run the ls9's because it is a different bore and ''doesnt make sense''....

i had an l33 in my last mustang. it made no less than 675hp its entire life. it dynoed at 854hp at 21psi and was ran on the street anywhere from 21 to 24psi. it NEVER, EVER pushed one drop of water. i have no idea how many miles it had, but it went through 10-12 sets of drag radials being driven only on the weekends...so a lot of miles. now here is the killer... i am not the fastest, most hp, or even the 100th guy to do this. my question to you is why wouldnt you run the ls9 gasket?

this is how the car was treated.
 

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Put the LS9 gaskets on it and quit worrying about if it makes sense or not...

Also... Grab a block of machinists stock thats long enough to go across the whole deck of the block and heads... some 2000 grit wet sandpaper, and machinists dye and prep the decks yourself...

If they've been milled flat and true... and you just need to get the ridges out and the finish up to snuff... do it by hand.
 

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Discussion Starter #7
The "aye's" have it on the LS9 gaskets. I'll order them right now.

I did check the block and heads for flatness, I'll prep the heads my own bad self.

Thanks folks,

Ron
 

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Can’t argue that the LS9 gasket works. Many run them with success. That doesn’t mean it it’s ideal for the application, or that another gasket wouldn’t sell better. “Better” may not be needed by most. How many suggesting the LS9 gasket have used a felpro “permatorque” 3.79” bore MLS gasket and really leaned on it?

Drill out the rivets on an LS9 gasket and take the energizer layer out (2nd layer) then lay it down on your deck. You’ll see the embossed portion of the gasket sits outside the iron sleeve on the small bore engines. The job of this layer is to help hold the gasket in place when the head it torqued down. It does a better job of this if it’s sitting on the iron sleeve. Makes sense to me anyway…

Kurt Urban explained this to me.
 

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Discussion Starter #11
Just a side note, it took 400 grit to remove the surfacing machining marks.
Finished with 600.
They look very nice now.
 

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where did you get the torq specs for the studs-I have the china studs, came with no torq specs, they directed me to the Ebay site which says to use 65
I guess having no torq specs in the box should have been a clue for me to not use them, lol-or the mains
 

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ls9 gaskets and you may need anotehr set of heads. they are thin already and if the were nipped flat once i def wouldnt do it again. i tq'ed my china specials to 85
 

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Discussion Starter #16
ls9 gaskets and you may need anotehr set of heads. they are thin already and if the were nipped flat once i def wouldnt do it again. i tq'ed my china specials to 85
We just did. A .003" clean up cut. Plus whatever I sanded to get to smooth.
I do see the advantage if an aftermarket heads much thicker deck though.
Not to mention better flow.
If I didn't mind having two cars apart for several weeks, I'd swap the AFR's from my vette over. But that's just not in the cards right now.

Ron
 

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in for results.. Best of luck Ron..
ls9 gaskets on my little 3.830 bore holding so far.. but I feel like doing a retorque for some piece of mind..
 
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