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What stock aluminum LS block will hold the most power. I run an filled iron 5.3 but looking for a lighter option. I would prefer not to fill the block because of the weight but will if needed. HP in the 1400 range.
 

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Many are using aluminum 5.3 blocks and running in the bottom 8's and high 7's. They will have the thickest sleeves as well compared to an alum 6.0 or 6.2. I've chatted with Steve Demirjian (RED) and he said that all 6.2's suffer from casting shift so the sleeves on most of them are not always an even thickness once finish machined. Some he said are really bad. The 6.0 block didn't suffer from this casting/production problem.
 

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Gen 3 or 4 5.3. Keep the bores as small as you can for the thickest wall possible. Many builders prefer the gen 3 to the gen 4 for main rigidity. Gen 4's have siamesed bores which is good.
 

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KEVIN CAPS LOCK
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HOW MUCH IS A DART COMPARED TO ALL OF THAT BS?
 

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Probably about $5K to start. I have priced a solid aluminum, tall deck, LSNext2 and it was only a couple grand from a billet block. I have a new in the crate LS7 2015 mfg date if anyone is interested. These were made before the quality got shitty. Its a Gen IV syle block, press-in sleeves, doweled steel caps, torque plate honed from factory. PM me if interested. I had a chance to buy two of them before they were discontinued at Motorstate Distributing. I am keeping the other one for myself.
 

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I saw this video with Eric Dillard of Pro-Line.. And he said that before they started producing billet engine blocks, they used cast aluminum blocks.. He said those cast blocks held up well, they just weren't as repairable as the billet blocks.. If someone were to put a connecting rod thru the side of them..

That made me think that maybe aluminum blocks are less incline to cracking as cast iron blocks..

My question is... What part of these factory cast aluminum blocks are prone to fail ??
 

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In the factory cast blocks it is more how much head seal you can get with only 4 bolts..... vs aftermarket block that has 6 bolts. Also when you finally step it up and put in a crankshaft that is $2-5K inside you stop the crank flex which the cheaper overseas forging will do at higher HP levels wearing out the main bearings. It's like anything car related.. beyond a certain HP level it is cubic dollars to make it reliable.
 

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HOW MUCH IS A DART COMPARED TO ALL OF THAT BS?
I can buy a complete aluminum 5.3 for between $500-1000. An aluminum dart block is 4K +
 
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ls1 s/s notch on 28s
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L33 short block i have here i got nothing in it..paid $300 for it,sold the 799s for $300. Still have complete intake,rails,tb an injectors i could sell for $100. I have Lq4 short im nothing in also after selling the heads,but it needs a crank so ill be $100 into it.

the ls shit is starting to go up..see people wanting $300 for 862/706 heads now when they where $100 for yrs..but if you network an hit local shops you can get stuff. I got 2 shops that hit me with any ls stuff because ill pay them more then the core fee or scrap yard.
 

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L33 short block i have here i got nothing in it..paid $300 for it,sold the 799s for $300. Still have complete intake,rails,tb an injectors i could sell for $100. I have Lq4 short im nothing in also after selling the heads,but it needs a crank so ill be $100 into it.

the ls shit is starting to go up..see people wanting $300 for 862/706 heads now when they where $100 for yrs..but if you network an hit local shops you can get stuff. I got 2 shops that hit me with any ls stuff because ill pay them more then the core fee or scrap yard.
I'm doing a 5.3 with LSA crank, molnar rods, and some diamond pistons. I don't have enough turbo yet for 1500 but will build the short block for that HP. I do think a partial fill would be a good idea as it will heap stabilize the block bottom end and keep the flex down. The block is stressed pretty hard at that level so I'd studd it and consider using my Rockin Block billet plates to convert to a 6 bolt head top keep them down too.

I'm still working on these plates but they essentially provide a poor mans 6 bolt block that I hope can take a stock block up to around 2k hp (we'll see!!)

at this level I believe a 6 bolt head with a thick deck will really make sense. PM me if interested
 

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L33 short block i have here i got nothing in it..paid $300 for it,sold the 799s for $300. Still have complete intake,rails,tb an injectors i could sell for $100. I have Lq4 short im nothing in also after selling the heads,but it needs a crank so ill be $100 into it.

the ls shit is starting to go up..see people wanting $300 for 862/706 heads now when they where $100 for yrs..but if you network an hit local shops you can get stuff. I got 2 shops that hit me with any ls stuff because ill pay them more then the core fee or scrap yard.
Tony,

I scrounge my truck bomb stuff from NC and I just found a guy right up the street from me who does fleet maint on trucks and vans He had the alum and iron blocks stacked like cord wood. I snagged an l33 complete with a 480LE and ecm (runs flex fuel) for 500 bucks. I couldn't believe it. He had receipts for the tranny being redone 30k ago. The reason for the cheap price is this engine popped a dod lifter and was making a racket and had over 200k miles. Bores looked incredible, this engine probably spent it's life in the 1-4k range in an express van.

deal are still out there, now I have those little guys stacked like cord wood too so if anyone needs an LS truck bomb core or built engine, the starting point is cheap!!!
 

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I saw this video with Eric Dillard of Pro-Line.. And he said that before they started producing billet engine blocks, they used cast aluminum blocks.. He said those cast blocks held up well, they just weren't as repairable as the billet blocks.. If someone were to put a connecting rod thru the side of them..

That made me think that maybe aluminum blocks are less incline to cracking as cast iron blocks..

My question is... What part of these factory cast aluminum blocks are prone to fail ??
On the early alum blocks like LS1 prior to 2003, the liners are really thin and will crack under high cyl pressure

for big power, I'd start with the gen4 as that block is much stronger.

rule of thumb (your results WILL vary)

Stock blocks

ls1 - 800
ls6 - 1000
LS9 - expensive but has piston squirters and billet main caps
LSA - 1200+ lacks the billet caps, but the block is very strong)
LS2 - likely the best "big bore" block for boost
LS3 - similar to LS2 in strength, but bigger bore not as good - thinner liner)
gen 4 L33 & variants - 1400 these blocks seem to be the preferred choice for a really high hp build
gen 5 ???? (blocks look stronger and the heads are taller with stiffer decks)

LSX 2500+


I thought about sleeving a gen 4 block with the darton stuff but it's really expensive and I don't think you gain all that much.

for much above 1400, I think the little iron blocks are a better choice as they are SOOO much stronger.

Ask a machinist how much the alum blocks move around during machining operations.
ERL 2000 (gutted blocks with the bridge girdle and 6 bolt tabs welded to block, no longer made)
Billet block (dart 3k + ??
 

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ls1 s/s notch on 28s
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I'm doing a 5.3 with LSA crank, molnar rods, and some diamond pistons. I don't have enough turbo yet for 1500 but will build the short block for that HP. I do think a partial fill would be a good idea as it will heap stabilize the block bottom end and keep the flex down. The block is stressed pretty hard at that level so I'd studd it and consider using my Rockin Block billet plates to convert to a 6 bolt head top keep them down too.

I'm still working on these plates but they essentially provide a poor mans 6 bolt block that I hope can take a stock block up to around 2k hp (we'll see!!)

at this level I believe a 6 bolt head with a thick deck will really make sense. PM me if interested
Talk to turbo above for block filler theres a guy who had a epoxy to use in them of you want to fill
 

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ls1 s/s notch on 28s
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25,925 Posts
Tony,

I scrounge my truck bomb stuff from NC and I just found a guy right up the street from me who does fleet maint on trucks and vans He had the alum and iron blocks stacked like cord wood. I snagged an l33 complete with a 480LE and ecm (runs flex fuel) for 500 bucks. I couldn't believe it. He had receipts for the tranny being redone 30k ago. The reason for the cheap price is this engine popped a dod lifter and was making a racket and had over 200k miles. Bores looked incredible, this engine probably spent it's life in the 1-4k range in an express van.

deal are still out there, now I have those little guys stacked like cord wood too so if anyone needs an LS truck bomb core or built engine, the starting point is cheap!!!
Sounds like you hit the jack pot.but yeah alot of them have nothing really wrong with them or little thing..my l33 was pulled for burning oil..the the lil oil cooler on the pan was leaking an had that side of the block caked in a 1/2" of oil..

Once you start scoring then youll start getting wild ideas..i have a gen 4 4.8 here i have setup for boost or a 400 shot.. ive been looking into nitro an going to try my hand with some on it i think..ill cut vp nitro 50-50 down to 10/15% at first an work my way up..been trying to figure out thw bsfc number to get a idea looking like 1.7 to use for injector size so some 212s will get me around 800 max with like 70 psi base an 80% duty..figure ill get the 4.8 around 400 on meth an be around 550 on a 50% mix..i know m5 to nitro 50 is about a 25% power increase
 
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