Resleeved block strength
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 673
From: Oskaloosa, Iowa
Resleeved block strength Is a resleeved block actually stronger?
I知 currently running an Ls3 block with forged rods/pistons around 1000 rwhp. Car runs 5.9x in the 1/8th at 3800 lbs. I知 going to move from the f1a-94 to an f1x. I will likely run it on the current motor but planning the next build since I知 on stock block and crank.
I saw a podcast with LME talking about resleeving actually weekend the block. It makes sense and since I知 boosted cubic inches aren稚 as important to me.
I知 considering a 388 but would like to stay aluminum. Options are resleeved block, lsx block or aftermarket aluminum but I知 not sure I want to spend aftermarket aluminum block type of cash.
Can a resleeved LS block hold up to 1200 rwhp or do I need to go aftermarket block or lsx?
I don稚 want to spend a bunch doing superdeck or whatever they call it. I would go aftermarket rather than do that
I also drive the car a lot so I don稚 want to fill the block either.
I知 currently running an Ls3 block with forged rods/pistons around 1000 rwhp. Car runs 5.9x in the 1/8th at 3800 lbs. I知 going to move from the f1a-94 to an f1x. I will likely run it on the current motor but planning the next build since I知 on stock block and crank.
I saw a podcast with LME talking about resleeving actually weekend the block. It makes sense and since I知 boosted cubic inches aren稚 as important to me.
I知 considering a 388 but would like to stay aluminum. Options are resleeved block, lsx block or aftermarket aluminum but I知 not sure I want to spend aftermarket aluminum block type of cash.
Can a resleeved LS block hold up to 1200 rwhp or do I need to go aftermarket block or lsx?
I don稚 want to spend a bunch doing superdeck or whatever they call it. I would go aftermarket rather than do that
I also drive the car a lot so I don稚 want to fill the block either.
Sleeved blocks Yes, the correct block sleeved with Darton dry liners is much stronger than a stock piece. Darton sleeves are at least three times the tensile strength of the cast in grey iron liners. Your LS3 block will hold 1200 rwhp with Darton sleeves installed. The strongest of the GM factory aluminum castings however is the LC9 5.3. This block has solid main bearing bulkheads greatly reducing the chance of cracking as can happen with breather hole blocks. Breather hole blocks can crack between the breather hole and cam bearing bore if leaned on hard. I have sleeved hundreds of LS blocks over the past twenty years for both shops and end customers.
__________________
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 673
From: Oskaloosa, Iowa
LME was saying in the podcast it痴 not the sleeve that is the issue it痴 the aluminum removed from the block for the sleeve that weakens them and the blocks fail at high power levels with boost not the sleeves themselves.
Well, I have sleeved well over 700 LS factory castings over the years. If you tune the block correctly and don't try to over due the power output I have not seen any issues. I stopped doing the MID wet sleeves on the LS blocks. This worked well on the original LS1 blocks with solid main bearing bulkheads and long head fasteners that tied the block together. Customers related back to me they would hold over 1700 horsepower. No good on the Gen IV blocks with short head fasteners. The safe limit on dry liners in a stock LC9 casting would be around 1250 rear wheel horsepower or 1500 at the flywheel. Any more than that I would recommend an after market block. I'm a Dart distributer for that reason.
__________________
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 673
From: Oskaloosa, Iowa
Well, I have sleeved well over 700 LS factory castings over the years. If you tune the block correctly and don't try to over due the power output I have not seen any issues. I stopped doing the MID wet sleeves on the LS blocks. This worked well on the original LS1 blocks with solid main bearing bulkheads and long head fasteners that tied the block together. Customers related back to me they would hold over 1700 horsepower. No good on the Gen IV blocks with short head fasteners. The safe limit on dry liners in a stock LC9 casting would be around 1250 rear wheel horsepower or 1500 at the flywheel. Any more than that I would recommend an after market block. I'm a Dart distributer for that reason.
I set 1200 rwhp as a goal based upon how much I'm willing to spend and the parts I think it will take to get there. I feel like 1200 rwhp is a safe limit for a stock block and 4 bolt heads. I'm sure someone has made more power with those parts, but I've seen enough failures either with lifting heads or issues due to block flex/failure beyond that point for me to draw the line there.
My plan is a 388 no matter what block I choose. For boost I feel that keeping the stock stroke is going to help everything survive better at those levels.
Teching In
Joined: Mar 2010
Posts: 48
Likes: 1
From: Sarasota,FL & NW Indiana
Sleeve length Well, I have sleeved well over 700 LS factory castings over the years. If you tune the block correctly and don't try to over due the power output I have not seen any issues. I stopped doing the MID wet sleeves on the LS blocks. This worked well on the original LS1 blocks with solid main bearing bulkheads and long head fasteners that tied the block together. Customers related back to me they would hold over 1700 horsepower. No good on the Gen IV blocks with short head fasteners. The safe limit on dry liners in a stock LC9 casting would be around 1250 rear wheel horsepower or 1500 at the flywheel. Any more than that I would recommend an after market block. I'm a Dart distributer for that reason.
Have a question for you. With a LC9 block, castings #12571048 or #12601900. what is the stock sleeve length for those blocks.
This is for a Suburban used for towing. Looking for Max Low Speed Torque Reliability. EX: 3.800-3.810 bore with 4 - 4.100 - 4.125.
If I go crazy, 4.25 stroke with one of your blank ( I-N4 ) sleeves machined to 3.80 - 3.810 bore.
(would like to keep displacement low when not towing)(fuel economy)
Thank you in advance
Jim
LC9 5.5" sleeve length with sharp edge, no chamfer. Darton LS sleeves are 5.800" long. I would recommend you go with the 300-023 sleeves which are roughed to 3.875" and go with the 5.7 bore size of 3.897". These sleeves are slightly less than $150 each. If you purchase blanks you will pay just about the same price as these finished sleeves. Not worth it. Not to mention issues with the valves clearing the smaller bore size. I question whether you would save enough money on gas to offset the price of building this engine unless you live in Ca. and drive a lot.
__________________
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Trending Topics
Is a resleeved block actually stronger?
I知 currently running an Ls3 block with forged rods/pistons around 1000 rwhp. Car runs 5.9x in the 1/8th at 3800 lbs. I知 going to move from the f1a-94 to an f1x. I will likely run it on the current motor but planning the next build since I知 on stock block and crank.
I saw a podcast with LME talking about resleeving actually weekend the block. It makes sense and since I知 boosted cubic inches aren稚 as important to me.
I知 considering a 388 but would like to stay aluminum. Options are resleeved block, lsx block or aftermarket aluminum but I知 not sure I want to spend aftermarket aluminum block type of cash.
Can a resleeved LS block hold up to 1200 rwhp or do I need to go aftermarket block or lsx?
I don稚 want to spend a bunch doing superdeck or whatever they call it. I would go aftermarket rather than do that
I also drive the car a lot so I don稚 want to fill the block either.
I知 currently running an Ls3 block with forged rods/pistons around 1000 rwhp. Car runs 5.9x in the 1/8th at 3800 lbs. I知 going to move from the f1a-94 to an f1x. I will likely run it on the current motor but planning the next build since I知 on stock block and crank.
I saw a podcast with LME talking about resleeving actually weekend the block. It makes sense and since I知 boosted cubic inches aren稚 as important to me.
I知 considering a 388 but would like to stay aluminum. Options are resleeved block, lsx block or aftermarket aluminum but I知 not sure I want to spend aftermarket aluminum block type of cash.
Can a resleeved LS block hold up to 1200 rwhp or do I need to go aftermarket block or lsx?
I don稚 want to spend a bunch doing superdeck or whatever they call it. I would go aftermarket rather than do that
I also drive the car a lot so I don稚 want to fill the block either.
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Verdad Gallardo Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 673
From: Oskaloosa, Iowa
@BCNUL8R -You mentioned superdeck blocks. If you're referring to the ERL blocks, ERL discontinued them a few years ago
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 673
From: Oskaloosa, Iowa
https://ls1tech.com/forums/generatio...ed-blocks.html
At his price point it has been determined you are better off buying a concept LSR block which is still much stronger and get 6 bolts per cylinder.
Lol. Check out this thread I already posted with this same video.
https://ls1tech.com/forums/generatio...ed-blocks.html
At his price point it has been determined you are better off buying a concept LSR block which is still much stronger and get 6 bolts per cylinder.
https://ls1tech.com/forums/generatio...ed-blocks.html
At his price point it has been determined you are better off buying a concept LSR block which is still much stronger and get 6 bolts per cylinder.
Lol. Check out this thread I already posted with this same video.
https://ls1tech.com/forums/generatio...ed-blocks.html
At his price point it has been determined you are better off buying a concept LSR block which is still much stronger and get 6 bolts per cylinder.
https://ls1tech.com/forums/generatio...ed-blocks.html
At his price point it has been determined you are better off buying a concept LSR block which is still much stronger and get 6 bolts per cylinder.
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 673
From: Oskaloosa, Iowa
I'll throw this out there. Unless you get some sort of screaming killer buddy deal on a LSR block, there is no way I would run that instead of a Dart alum block. I'm not saying the LSR is bad, but once you get to that level an extra $500-1000 for extra strength is well worth it. The main caps on the Dart are better too. I haven't seen an LSR make 2000+hp, but have several Dart alum make that and more.
I plan to get the new f1r-103 blower when it痴 released. Power numbers haven稚 been released as it痴 still in testing but f1x power in a smaller package has been mentioned.
I plan to run that blower on my current motor if I don稚 hurt it before then lol.
I don稚 expect to make more than 1300 rwhp at best on a new motor giving the blower all it can do.
I still haven稚 ruled out trying a resleeved lc9 block for what I知 tying to do yet either.
Teching In
Joined: Mar 2010
Posts: 48
Likes: 1
From: Sarasota,FL & NW Indiana
Dart SHP Next LC9 5.5" sleeve length with sharp edge, no chamfer. Darton LS sleeves are 5.800" long. I would recommend you go with the 300-023 sleeves which are roughed to 3.875" and go with the 5.7 bore size of 3.897". These sleeves are slightly less than $150 each. If you purchase blanks you will pay just about the same price as these finished sleeves. Not worth it. Not to mention issues with the valves clearing the smaller bore size. I question whether you would save enough money on gas to offset the price of building this engine unless you live in Ca. and drive a lot.
Thank you for the information. While on your website< noticed you are a Dart dealer.
Have you measured the SHP cylinder length?
I realize the Dart states .375 longer, but from what comparison?? Iron @ 5.430 or AL @ 5.500
Would you be comfortable with a 4.125 stroke? (low RPM towing&DD Suburban)
Thanks again
Jim
Last edited by jjtoma; Sep 8, 2025 at 03:02 PM.
I don't know what the cylinder length is on the SHP block. I'm sure if you call Dart someone there can help you with this.
__________________
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Teching In
Joined: Mar 2010
Posts: 48
Likes: 1
From: Sarasota,FL & NW Indiana
SHP block Steve suggested that I called Dart. So this morning called Dart.
The tech person who answered went in the back and measured a SHP block said it was 5.750 !
Then I called HPR, Anthony said the iron blocks are 5.500 & aluminum is 5.750
Now thinking, I'll take Steve's suggestion & sleeve a 5.3L block as discussed earlier in the thread.
(at least I know what I'm working with)
I'll order my pistons thru HPR since they have done so many of these LS strokers for a long time.