How much boost can a ls7 block handle? Does anyone have a race engnering block?

[Rumbumbees$ponsor]

Like it says how much boost can a LS7 block handle?

Does anyone have experience with the darton sleeved LS1 aluminum truck block?

[blake-b]

I've got an ls2 darton MID wet sleeved block being built into an engine very soon.

[Unreal]

RED does good stuff.

Blocks don't care about boost. They care about cylinder pressure. I could get a ls7 block to hold 40+psi if needed by putting some stock ls1 heads on it, restrictive intake, and only make 600rwhp on 40psi. Boost does not matter at all.

Friends 427 setup see 32psi maxing out a Ysi, I see 24, just difference in heads/cam/intakes/headers. Same power, same stress on block, just difference boost levels because boost is just a restriction measure.

[SuperchargedStealth]

Originally Posted by Unreal

RED does good stuff.

Blocks don't care about boost. They care about cylinder pressure. I could get a ls7 block to hold 40+psi if needed by putting some stock ls1 heads on it, restrictive intake, and only make 600rwhp on 40psi. Boost does not matter at all.

Friends 427 setup see 32psi maxing out a Ysi, I see 24, just difference in heads/cam/intakes/headers. Same power, same stress on block, just difference boost levels because boost is just a restriction measure.

What he said. To answer your question in a way you can better understand, A stock LS7 block is basically a LS3 block, bored to a LS7. Doing this makes the cylinder walls thinner leaving it vulnerable to heat which can lead to the sleeves melting. More boost, more heat. You can run meth, or nitrous to aid in heat, but a more positive way to approach it is by having the sleeves replaced with stronger ones, or by switching to a LSX block. I've seen boosted LS7's run ~6-8 lbs of boost and nitrous. They run strong and the owners aren't too concerned about anything.

[AGP Turbo]

It's the most expensive of all the LS blocks and the worst for high power. Just go LS3 stock sleeves slightly bored to fit pistons and 4" crank. If you need more power than that will handle, LSX.

[SuperchargedStealth]

Originally Posted by AGP Turbo

It's the most expensive of all the LS blocks and the worst for high power. Just go LS3 stock sleeves slightly bored to fit pistons and 4" crank. If you need more power than that will handle, LSX.

What a lot of people don't like about the LSX is the added weight. Granted it's about 100 lbs. heavier, but it can take the beating. It might be naive to think this way, but the way I look at it, is that the extra weight helps keeps the front end more planted to the ground. I noticed prior to my LSX, that when I got on it, the front end lifted and got a little light in the front end.

[AGP Turbo]

If you want a nice reliable 1100+whp you just gotta deal with the extra 100lbs.

[Rumbumbees$ponsor]

Here are the problems...

1. LSX to heavy, its bad ass but last thing i want is more weight.

2. I want bigger bore and stroke not just stroke... problem LS3 is to thin to punch to 4.125, and it sounds like the LS7 shouldn't be used for boosted applications. resleeving is to much to, especially with core charges.

I did see that a 5.3l alum truck block is stronger plus core is cheaper. resleeving and the labor to machine the rest wasnt to bad.

I may just get a good set of rods and pistons and reuse stock crank and go 5 over.. like i said i really dont want a 416-19 with practically same bore.

If i did lsx block i go 4.150 or .155 and 4.100 crank after all the chatter 4.185 is to risky

[Unreal]

Resleeved ls2/3/7/5.3/etc etc are all strong. No reason to start with expensive ls7 block. A sleeved block will handle 1000 just fine. From there heads become an issue.

[stevieturbo]

Originally Posted by Rumbumbees$ponsor

Here are the problems...

1. LSX to heavy, its bad ass but last thing i want is more weight.

2. I want bigger bore and stroke not just stroke... problem LS3 is to thin to punch to 4.125, and it sounds like the LS7 shouldn't be used for boosted applications. resleeving is to much to, especially with core charges.

I did see that a 5.3l alum truck block is stronger plus core is cheaper. resleeving and the labor to machine the rest wasnt to bad.

I may just get a good set of rods and pistons and reuse stock crank and go 5 over.. like i said i really dont want a 416-19 with practically same bore.

If i did lsx block i go 4.150 or .155 and 4.100 crank after all the chatter 4.185 is to risky

Wanting a bigger bore and it being any real benefit are two different things.

And the 5.3 is stronger...because it doesnt have a bigger bore.

Sleeve it out to a large bore, and it will no longer be as strong.

[bowtienick]

Livernois has the option of building a big bore ls3. Pretty reasonable and not requiring a core.

[2010SSRSM6]

BlazinDorito is selling a fully built LSX 434 that was making 1500+ hp with his TT setup. His car is ridiculous.


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[SuperchargedStealth]

Originally Posted by Rumbumbees$ponsor

Here are the problems...

1. LSX to heavy, its bad ass but last thing i want is more weight.

2. I want bigger bore and stroke not just stroke... problem LS3 is to thin to punch to 4.125, and it sounds like the LS7 shouldn't be used for boosted applications. resleeving is to much to, especially with core charges.

I did see that a 5.3l alum truck block is stronger plus core is cheaper. resleeving and the labor to machine the rest wasnt to bad.

I may just get a good set of rods and pistons and reuse stock crank and go 5 over.. like i said i really dont want a 416-19 with practically same bore.

If i did lsx block i go 4.150 or .155 and 4.100 crank after all the chatter 4.185 is to risky

The LS7 is essentially an LS3 bored to a 4.125. If you purchase an LS7 you'll be spending more money on a built motor rather then actually having a motor built. If that makes sense. The LS7 is expensive partly because of it's background application ie. the Z06. It's a waste of money. ERL makes resleeved aluminum short blocks for less then what you would pay for an actual LS7. Also add in the fact that it's a fully built motor with quality parts, your still making out on top with a more reliable motor and it weighs about the same as an LS7. With an LSX or and ERL built motor, you'll be able to utilize the 6-bolt head pattern just like the LS7. Also, FYI, a stock LS3, 416 etc. have the same stroke. It's the bore that's different. I believe that when you get to a 427, that's when the stroke changes.

BTW, what are your goals and what type of racing are you doing?

[1KillerSS]

Originally Posted by Rumbumbees$ponsor

Here are the problems...

1. LSX to heavy, its bad ass but last thing i want is more weight.

2. I want bigger bore and stroke not just stroke... problem LS3 is to thin to punch to 4.125, and it sounds like the LS7 shouldn't be used for boosted applications. resleeving is to much to, especially with core charges.

I did see that a 5.3l alum truck block is stronger plus core is cheaper. resleeving and the labor to machine the rest wasnt to bad.

I may just get a good set of rods and pistons and reuse stock crank and go 5 over.. like i said i really dont want a 416-19 with practically same bore.

If i did lsx block i go 4.150 or .155 and 4.100 crank after all the chatter 4.185 is to risky

Are you seriously worried about 100lb? I would take the extra weight in a second for the power trade off.