5.3 best head gasket for boost?
 

Putting an aluminum LC9 5.3 bored to a 3.800 with a 4.000 stroke crank into my 2008 corvette for my twin turbo build. Most of the time i plan to keep boost in the high teens, but wouldnt mind touching 25PSI occasionally. Motor will have ARP head studs and trick flow 220 heads. I was about to order LS9 head gaskets since Ive always had good luck with them on LS2/LS3 motors, but this is my first small bore build. Any thoughts? Anyone out there running big boost on a 5.3 and LS9 gaskets without issues?

Thanks!

Ls9s . I put 32# from a 88mm on a sbe 5.3 and ls9s.

^This. Regardless of people complaining about the bore size.

Does the LS9 gasket fire ring cover the sleeve or is it on the edge and onto the alum deck?

Agree, LS9 gaskets have seen it all, dont flinch at 32+ from a 94mm. I tried the 5.3 HO gaskets, blew out both sides in a few passes.

Thats what i figured, just wanted to double check. Not too many guys with 5.3s over on the corvette forum. Just got a great deal on some OEM LS9 gaskets from rock auto. Thanks guys

bore size too big. crevice area no good.

:jest:

When theory doesn’t match reality, it’s time to come up with a new theory.

Can I get an Amen!?

Vette guys are scared to go fast :jest:

Why would it matter? Are you saying aluminum can’t seal? Well, somebody better tell all those aluminum heads!

Trust me i still feel a little funny removing the mint 19k mile 427ci LS7 out of my z06 to put in a "junkyard" 5.3 but i keep telling myself it will be worth it lol

I wonder if it seals as well as it would if it sat on the sleeve. When I did have an LS9 gasket let go on an LC9 (my fault) it torched the deck and head in a spectacular fashion! lol... I wonder if it would have stayed in place a little better and not hurt the deck as much with a 3.8" bore gasket. I still Toss ls9's on everything because that's what has worked for me in the past, just curious. Kurt Urban has worked on MANY big power setups and defiantly didn't like how they sat outside the sleeve. I feel his experience and opinion trumps mine and then some.


https://cimg3.ibsrv.net/gimg/ls1tech...bcc433b1b6.jpg
https://cimg1.ibsrv.net/gimg/ls1tech...1fb60c6aee.jpg

Kurt is beast. I'm sure max effort or class racing would dictate a more meticulous level of detail.

As 86 pointed out, less gasket stability when not fully seated on the sleeve. Alum head - no problem since it runs completely on alum deck with no transition.

Whats the 5.3 SBE record with a LS9 head gasket... 7.1 these days? Seem to be just fine even in racing. LS9 gasket has gone a ton faster on a 5.3L than the guys that spent $400 on woodoo gaskets and $10k+ engines :jest:

True enough! Though that's like saying guys have gone 7's with an ls1 intake manifold. True statement, but does that mean its optimum or "the best" intake for a 7 second combo?

Is an LS9 "the best" head gasket? I really don't know! They are good enough for me and my $500 short block! Wish I had the courage to try the standard cheap MLS gaskets. Or to reuse the wall full of undamaged used LS9 gaskets I've accumulated over the years. :D BTR also has their version of the LS9 that's a little cheaper than the OEM LS9 gaskets.

Agree, always improvements to be made. Wasn't too long ago people were scared to run more than 10 PSI on an SBE LS. I think most of the fancy Athena/cut ring style gaskets come with larger bores as well, smallest I've seen is in the 3.9-4.0 bore range. Not much fancy stuff out there for small bore stuff. Undamaged gaskets, hit them with some copper spray and send it :jest:

Any of you guys pushing 5.7's more than 1 bar not on E85?