jleews6

iTrader: (2)

Whats everybody's opinion on this? I know the 5.3 has the thicker sleves but what about the LS3 or LS2 block?
Thanks

JoeNova

The 5.3 IS the strongest aluminum block.

SenorThumpy

Is there actually a durability issue with the alumn blocks? I understand that re-sleeving the actual LS motors isn't really feasible and that isn't really THAT big of an issue, atleast not as far as i'm concerned. You're really only going to need to do that if you have some catastrophic failure. I don't really consider that a durability issue.
I also understand the cyl walls are thinner on actual LS motors but at what point does that actually become an issue? Wouldn't you have to be running crazy boost or compression for that to actually be an issue?
Am I missing something?

The Alchemist

iTrader: (19)

Well, there is a lot to be said that the ZR1 used essentially an LS3 block. (LSA/LS3, I haven't heard of any significant differences between the two).

JoeNova

The sleeves aren't necessarily an issue unless its an early LS1. Sleeves aside, all of the extra material in the 5.3 block greatly increases torsional rigidity.

I hear that there were lots of improvements to strength of the main webbing over the LS2 blocks once the LS3 blocks rolled out. I'm not sure if those changes took place in the newer 5.3 blocks or not.

mkvamso

iTrader: (2)

Ls3 blocks have much more webbing than earlier aluminum blocks
Supposed to be something like 30% more rigidity

rotary1307cc

iTrader: (5)

Late 5.3 aluminum much stronger than ls3

Tuskyz28

I agree!! That's what Steve @ Racing engine development told me.

SenorThumpy

So I did not know about the additional webbing/support but again, when does torsional rigidity of the block actually become an issue? Obviously we all want the best and the strongest parts that are available but I can't see this being something that has any impact on 95% of the vehicles on this forum. I could see a block possibly flexing or cracking in a full blown max effort race car making like 1500+hp but I just can't wrap my head around it being an issue for anything less than that. And at that power level your probably not even considering using a stock block.

I would love to be enlightened if this actually is an issue and something to be concerned about.

codyvette

iTrader: (24)

Even if there is not enough distortion for catastrophic failure, any block, crank, valvetrain distortion causes HP loss. This was evn more of an issue when SBC's started getting close to the quad didgit HP numbers.

jleews6

iTrader: (2)

Exactly, Even though a motor might live at say 1000HP doesnt mean that its not flexing or getting cap walk problems witch in turn will murder the bearings and other components.
In todays world 1000HP boosted LS motor is not as uncommon as it once was so why not use the best block available. I think that even the stroke has a pretty good effect on how much "flex" a block will have.
Thats why i asked because I know there are allot smart guys with allot of experience on here.

oscs

iTrader: (19)

Personally seen 2 LS2 blocks flex and take out mains around 1000whp. So I would say yea the extra webbing is defiantly a plus. However all this is for nothing with only 4 bolts per cylinder. Much more than 1000whp and it's basically a wash.

SenorThumpy

Well I learned something today I've never heard of block flex being an issue and never imagined it could be something to actually worry about. Good lesson!

There are indeed many smart people on this forum who know much more than I ever will. Thats one of the biggest reasons I subscribe to this particular forum.

My comment about not using a stock block at the 1500hp-ish mark was in reference to the 4 bolt mains.

rotary1307cc

iTrader: (5)

The upper cylinder is where the 5.3 is so much stronger. The upper bore is where you will see true failures with an ls3/ls2 being pushed

The Alchemist

iTrader: (19)

I forgot about the current 5.3 aluminum motor. What is that block designation?

Honeycutt

Don't forget about pinning the main caps either. That will help a lot with the caps walking. Fireball ran 7s at close to 200 with an LS2 block with pinned mains. A newer 5.3L aluminium block with pinned mains would probably be the strongest.

I have read a few things about the LSA/9 block being somewhat stronger than your run of the mill L92/LS3 block, but I'm not sure how much truth there is to it.

LJMSJohn

ZR1 was an LS9 block

Alot of differences in an LS9 block and an LS3 block...

LS9 has oil squirters, LS3 does not

LS9 has 12mm head fasteners LS3 has 11

LS9 has steel main caps, LS3 does not.

Theres more but thats 3 off the top of my head.


LS9 is the strongest stock aluminum block.... followed by a later 5.3 block/LS3/LS2.

oscs

iTrader: (19)

Pinning main caps is a waste of time on a 4 bolt block IMO

Honeycutt

Meh, like you said, that's an opinion. The caps will start moving around the 4 digit mark, 1000hp is not the magic number where you start lifting heads, there are more than a handful of people making over 1000hp on a 4 bolt block. Pinning the mains is a minimal cost compared to an LSX block.

jleews6

iTrader: (2)

So what is the designation for these later 5.3 motors ? Are they still called the L33?