Hey,

Replacing my 402 LS2 with a larger displacement engine. I was going to build an LS7 but decided to go another route.

Looking to sleeve an LS3 block with Darton MID system

http://www.dartonsleeves.com/midinfo.html

This way I have the ability to go up to a 4.200 bore RELIABLEY .. and the LS3 block is stronger than the LS7 block.

Weight is an issue and that's why an LSX block is out of the question.

Still checking on pistons so I'm not sure what bore size I will end up with, but what stroke could I run? I know 4-inch is good since that's what my LS2 is running, but would 4.125" run into issues? A 4.125 stroke along with a 4.125 in bore would give me a 440 alum engine, which would be good.

I'm mostly concerned with the extra stroke hitting the windage tray and pan. I already had to shim the windage tray and notch the pan. It's a Canton f-body style pan and I HAVE TO run it in my application.

Then again, if i just get a 4.200" bore piston I can keep my 4" stroke and call it a day.

Thoughts?

Oh, NA engine, hydraulic cam, FAST intake..

 

My 441 has a 4.125 bore and 4.125 bore. For an N/A build I don't think needing the stronger block really matters much and I may be wrong here but I think there is a problem running a 4.125 stroke in an LS3. Aren't the bores to short for that stroke?
I like the idea of the 4" stroke with the bigger bore (Darton Sleeve) to get the cubes but with a hydraulic set up the 4.125 stroke doesn't hurt things.
Now if you did build a 4" stroke LS3 441 you could always go solid roller down the road and take advantage of the shorter stroke for the higher rpms.

 

Yea, the bores are short for a 4.125 stroke.. unless you have shiny new (and longer) sleeves installed.

I suppose I will know more when Wiseco calls me back and I find out how big of a bore I can go (up to 4.200)...

My ideal setup would be a 4" stroke and close to a 4.200" bore (netting just over 440 cubes).

 

My suggestion would be to build a 454 with 4.185" bore and 4.125" stroke if the rods will clear your oil pan. The windage tray will need to be spaced down a bit more for clearance.

I have done several of these blocks for 454 builds and all are running fine.

Wiseco can make pistons to work with 4.125" stroke and the 5.800" sleeve length of the MID liners.

You will need better heads than you are running on a 402 for a large engine.

Steve

 

Or I could go with a 4.185 bore and 4" stroke for a 440, right?

my windage tray has already been shimmed down for the 4" stroke.. not sure what my limit is on doing this.

I imagine it would rev a bit slower with the longer stroke, right?

 

I'm in the middle of doing the same thing. Steve installed the Darton MID Sleeves on my blown up LS3 block and Charlie at RPM is building the motor. I am going with 4.155 bore and 4.000 stroke which will give me 434ci. I like revy motors so I did not to go more than 4" stroke.

Karn

 

I am not sure 1/8 of an inch additional stroke will slow down the rev capability of an LS too much. Lots of BBC's spinning up pretty high with much more than 4 inch stroke.

Check out this link - this puppy runs over 8000 rpm with a 5.75 inch stroke!

http://www.sonnysracingengines.com/e...-racing-engine

 

Just not sure if the 4.125 stroke will be a royal PITA in regards to hitting my oil pan and such. With the 4" stroke I already had to shim my windage tray down to clear.

Anyone run that stroke on an f-body pan? Any issues?

Now I just need to sell off my forged 402 LS2.. does it ever end?

 

i would run a resleeved ls3 block (dry sleeved) i would do 4.125 bore and stroke, i have done several of these using REDs blocks. as far as longer stroke not clearing the windage tray you can also run a callies crank and rods with a 2" rod journal (instead of 2.100") this helps a bunch with clearance issues ... i have run them in the past with great success as well, if you have any questions give me a call i even have a 447 motor (4.155 bore 4.125 stroke)sitting on the stand assemble that you can take a look at if you stop by the shop

p.s the 4.125 stroke will clear the f-body pan with some massaging

 

Thanks Ryan.. we should talk. I'm always looking for local shops to do engine builds at (for stories).. and you're a lot closer than Oceanside. Besides, it's more fun to spread the love around. lol

Although, I'm pretty set on the Darton MID sleeve deal.

I have a question.. if you were to sleeve an LSA block would that negate the oil squirters?

 

Steve:

Why do you have a picture of a 68 when your user name is 1969LS1?

 

Because my previous car was a 69 with an LS1 engine.. I never bothered to change my screen name here, but on other sites it's "Steve1968LS2".. heck on one old site it's "Steve2000SS" lol

I should just change them all to Brad Penny

You can see them all here: http://www.fquick.com/Steve1968LS2

 

How much power are you trying to make? Where did you get the information that a LS3 block is stronger than an LS7?

I better tell that to the guys running LS7 blocks in their twin turbo 1100 horsepower engines.

Oil squirters are your friend. In a long term durability test the oil squirters will aid in the cooling of the pistons. If your looking at short bursts and just a street/strip deal then you could delete them.

Robin

 

Never heads of the LS3 block being stronger than the LS7 block until its sleeved...
My motor will be making a near 925hp at the crank after nitrous and i am not second guessing the block or internals.
But why not do a 4.130 bore and 4.100 stroke?

EDIT: what are you looking to rev to?

 

Thats a minor thing that can be solved easly. Moroso oil pan with washers to shim it for a 4.100 stroke.

 

The LS3 being stronger than the LS7 is fairly common knowledge.. and it came from GM. And I never said LS7 blocks were weak.. just that the LS3 blocks are said to be a bit stronger.

They increased the block strength of later LS3 blocks to hold up to the demands from the supercharged LS9 (which uses the LS3 block).

We road race, so the squirters would be a plus. Not sure if they survive the sleeving process though.

 

In my application I need the front of the pan (thickness) to be less than or equal to a f-body LS pan.

 

Damn.... Well i guess you could cut a pan and get a good Tig welder.

 

While I still had some inside connections at GM I was told that the LS7 Blocks were stronger than any aluminum OEM block. The C5R was the one you want if your serious.

The story about LS7 blocks being weak is an internet myth.

The people that I know are using the LS7 as the base of their builds.

I think that several years ago there were some perceived failures that were blamed on the sleeves. From what I have seen any road race application will need additional ways to remove heat from the piston or upper cylinder area.
If you cannot transfer the heat from the combustion chamber, piston or cylinder your going to hurt parts. A lean mixture or inadequate cooling system in a road race environment are killers.

Notice that the ring land area on the LS3 pistons is hard anodized. There has to be a reason. One could assume that there could be a long term issue with the heat in the rind lands. With the thin rings being used today they are a lot more susceptible to loosing tension due to heat.

Heck when the L92 bare blocks were released there was a huge cry about the sleeves being "off center". Some of the people in that industry were ready to "improve" on the block for a modest fee.
Have you heard about problems with the L92/LS3 blocks?

In a road racing application I would jump on the C5R block. The technology that went into that block has not been matched in the aftermarket. From a durability standpoint it is hard to beat.

Several of the aftermarket Aluminum and Iron blocks have upgrades that the modified OEM blocks cannot match. The priority main oiling comes to mind.

In my application we raised the cam by .078. We also installed .937 lifters for durability with the high lift and spring pressures.
An OEM block lifter area would not support these types of components. OK not everyone runs .970" of lift but you get my point.

My buddy Paul Brown at Tiger Racing runs a warmed over LS7 in their Morgan Road Race car. They love that engine!

There are a lot of choices out there, good luck with your build.

Robin

 

Once again.. I NEVER SAID the LS7 was weak.. I said I wanted an LS3 over an LS2 block since the LS3 is stronger than the LS2 by something like 20%...

An LS7 for this is pointless since we're doing a resleeve.. it's just waisted money.

But thanks for your input, I just don't want people getting confused as to what I said. Thanks