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I have a LSX 454 that I bought used 3 years ago. I'll try to keep this as short as possible.
I rebuilt this thing twice already.
Setup is: 2008 C6 Z06 LSX 454, 4.200 Bore, 4.185 Stroke, Custom Spec Stage 2 LS7 Cam (Will change), RHS LS7 Pro Elite Cyl Heads 291CC, Comp Shaft Mount Rockers, ARH 1 7/8 Headers, FAST 102 (Will change to Mamo MSD), ID1050x Injectors.
My question is, can I boost this thing? Would you do it on a 4.200 bore which is the max bore size after which it will need resleeving on the next rebuild I'm guessing.
If so, would you procharge it at around 10psi or around a 200 shot of NOS? Why and why not?
This thing proved to be a money pit lol. But so far from the last build and tune it has all been going great so far. Fingers crossed.
Appreciate any input.
Last edited by 20SS06; Oct 17, 2021 at 01:59 AM.
Reason: removed wrong picture
That doesn’t look like a lsx454 block it only has 4 bolt heads.
I’ve read people have problems boosting the lsx454 blocks. But someone hear will know for sure.
That doesn’t look like a lsx454 block it only has 4 bolt heads.
I’ve read people have problems boosting the lsx454 blocks. But someone hear will know for sure.
First thing I noticed, as well as too much meat between the cylinders. A 4.2” bore is crazy thin between the holes.
Having said that, a 4.2” iron based build is going to be much stronger than a 4.2” aluminum build. 10psi isn’t a lot of boost by today’s standards. The elephant in the room here, is what happens when you get bored with the 10psi and want to jump it up to 15-18psi? Oh yes you will!
That is not a LSX454 block. Read the part number cast into the block if you want to cross check what it was originally. It's on the back side if I remember right.
LSX will have provisions for 6 bolt cylinder heads. To answer your question though it's not recommended to exceed 4.125 bore or 4.000 inch stroke for power adders.
Last edited by 01CamaroSSTx; Oct 16, 2021 at 12:39 PM.
I have a LSX 454 that I bought used 3 years ago. I'll try to keep this as short as possible.
I rebuilt this thing twice already.
Setup is: 2008 C6 Z06 LSX 454, 4.200 Bore, 4.185 Stroke, Custom Spec Stage 2 LS7 Cam (Will change), RHS LS7 Pro Elite Cyl Heads 291CC, Comp Shaft Mount Rockers, ARH 1 7/8 Headers, FAST 102 (Will change to Mamo MSD), ID1050x Injectors.
My question is, can I boost this thing? Would you do it on a 4.200 bore which is the max bore size after which it will need resleeving on the next rebuild I'm guessing.
If so, would you procharge it at around 10psi or around a 200 shot of NOS? Why and why not?
Below pic attached from last rebuild to give you an idea of the cylinder walls.
This thing proved to be a money pit lol. But so far from the last build and tune it has all been going great so far. Fingers crossed.
Appreciate any input.
First off, a 4.200 bore and a 4.185 stroke=464 cubic inches, NOT 454. Secondly, I agree with the rest as far as having too much meat between cylinders, and only a 4 bolt head bolt circle. Have you actually measured the bore and stroke? I hate to say it, but I'm wondering if you have an LQ9 CI block?
That doesn’t look like a lsx454 block it only has 4 bolt heads.
I’ve read people have problems boosting the lsx454 blocks. But someone hear will know for sure.
I just noticed actually. Never paid attention TBH. But I do remember that they called me in the shop once and checked and it actually is an LSX. I wondered if it were the color they saw or the engraved ID or wtv. They told me they read it. Did LSX's ever come in a 4 bolt configuration?
Originally Posted by Che70velle
First thing I noticed, as well as too much meat between the cylinders. A 4.2” bore is crazy thin between the holes.
Having said that, a 4.2” iron based build is going to be much stronger than a 4.2” aluminum build. 10psi isn’t a lot of boost by today’s standards. The elephant in the room here, is what happens when you get bored with the 10psi and want to jump it up to 15-18psi? Oh yes you will!
lol oh no Im done with money pits. 10psi or lower even
Originally Posted by QwkTrip
That is not a LSX454 block. Read the part number cast into the block if you want to cross check what it was originally. It's on the back side if I remember right.
Why so many rebuilds?
3rd owner of the car. I bought it and was immediately thrown into the money pit lol. I kept changing out parts every 500mi from the whole car not just the engine. I need to check the part number myself and see. According to the original shop who did this build in the US, Hardcore Racing Parts, it is an LSX 454, 4.185 Bore, 6.125 rods, 4.125 Stroke. It was also confirmed in the shop here in the UAE. So I'm not sure if all 3 of us owners got robbed by them or not.
Originally Posted by grinder11
First off, a 4.200 bore and a 4.185 stroke=464 cubic inches, NOT 454. Secondly, I agree with the rest as far as having too much meat between cylinders, and only a 4 bolt head bolt circle. Have you actually measured the bore and stroke? I hate to say it, but I'm wondering if you have an LQ9 CI block?
Correct. I know it is 464ci but just said 454 to refer to the original block of this build. Yes, I was there for the measurements and I bought a custom set of Wiseco 4.200 bore pistons when we were doing the rebuild.
The guys at the shop here checked and it did seem like an LSX block they checked the casted part number apparently. Also, according to the original builders of this engine "Hardcore Racing Parts", it is an LSX 454, 4.185 Bore, 6.125 rods, 4.125 Stroke I'm not sure if this whole engine should be dumped or not at this point lol.
Here are some more pics in the hope of anyone being able to identify what block this really is lol. Thread moved from boost to wrong block real quick hahaha
Last edited by 20SS06; Oct 17, 2021 at 01:58 AM.
Reason: deleted wrong pictures
People began using a slang term LSx when they talked about LS engines in general and all the variants. The "x" is a placeholder for 1, 2, 3, 7 or whatever. Then GM decided to trademark LSX for a line of crate engines that are different than production engines. And some aftermarket companies decided to use LSX in their product names and that has created all kinds of confusion.
I can guarantee you do not have an LSX (GM trademark) racing engine block. It also did not start life as a 454. It was probably born a 5.3 or 6.0 for a truck.It is fairly common for shops to take a 5.3 (because the block is cheap) and re-sleeve it with aftermarket cylinder sleeves, and then size the bore to what they want. So it could have been a 454 cubic inch engine, but probably based on a production truck block. It's kind of important to know what sleeves you have in that engine in order to decide how much power you can put to it.
People began using a slang term LSx when they talked about LS engines in general and all the variants. The "x" is a placeholder for 1, 2, 3, 7 or whatever. Then GM decided to trademark LSX for a line of crate engines that are different than production engines. And some aftermarket companies decided to use LSX in their product names and that has created all kinds of confusion.
I can guarantee you do not have an LSX (GM trademark) racing engine block. It also did not start life as a 454. It was probably born a 5.3 or 6.0 for a truck.It is fairly common for shops to take a 5.3 (because the block is cheap) and re-sleeve it with aftermarket cylinder sleeves, and then size the bore to what they want. So it could have been a 454 cubic inch engine, but probably based on a production truck block. It's kind of important to know what sleeves you have in that engine in order to decide how much power you can put to it.
What he said. You're correct on which sleeves he has, too. I had a Darton sleeved LS1 block, machined and built back in 2005. The max safe bore on those "earlier" sleeves was 4.160. Later designed Darton sleeves could safely go to 4.200". You could probably bore the 4.160" max sleeves another .040", but it wouldn't be a good idea, and the "safely" part is gone. If you throw boost at something like that, it's a recipe for disaster....
Last edited by grinder11; Oct 16, 2021 at 06:02 PM.
Them are 2 different engines the orange one (is a LSX block) you can see the 6 bolt provisions the black block has only 4 bolts.
This. Two different engines. One even has billet main caps with studs, while the other is an Oem ls block with powdered caps and TTA Oem bolts. I think we are being played here personally. No way the OP doesn’t see the differences in these two different engines in the pictures.
Them are 2 different engines the orange one (is a LSX block) you can see the 6 bolt provisions the black block has only 4 bolts.
Originally Posted by grinder11
I wonder if it's a Darton sleeved LQ9? There must be some sort of casting/part numbers on it somewhere.......
Originally Posted by QwkTrip
People began using a slang term LSx when they talked about LS engines in general and all the variants. The "x" is a placeholder for 1, 2, 3, 7 or whatever. Then GM decided to trademark LSX for a line of crate engines that are different than production engines. And some aftermarket companies decided to use LSX in their product names and that has created all kinds of confusion.
I can guarantee you do not have an LSX (GM trademark) racing engine block. It also did not start life as a 454. It was probably born a 5.3 or 6.0 for a truck.It is fairly common for shops to take a 5.3 (because the block is cheap) and re-sleeve it with aftermarket cylinder sleeves, and then size the bore to what they want. So it could have been a 454 cubic inch engine, but probably based on a production truck block. It's kind of important to know what sleeves you have in that engine in order to decide how much power you can put to it.
Originally Posted by grinder11
What he said. You're correct on which sleeves he has, too. I had a Darton sleeved LS1 block, machined and built back in 2005. The max safe bore on those "earlier" sleeves was 4.160. Later designed Darton sleeves could safely go to 4.200". You could probably bore the 4.160" max sleeves another .040", but it wouldn't be a good idea, and the "safely" part is gone. If you throw boost at something like that, it's a recipe for disaster....
Originally Posted by Che70velle
This. Two different engines. One even has billet main caps with studs, while the other is an Oem ls block with powdered caps and TTA Oem bolts. I think we are being played here personally. No way the OP doesn’t see the differences in these two different engines in the pictures.
Originally Posted by G Atsma
Either this, or the OP was had and just didn't know the difference. But you're likely right.
Originally Posted by QwkTrip
What's the story behind the orange short block? That one looks like a real LSX block.
Originally Posted by G Atsma
To show what a real LSX block looks like.
Originally Posted by QwkTrip
OP has two engines in his picture set. One appears to be an LSX. I want to know the story behind those two engines.
I don't know how this happened lol but I was half asleep uploading pics. You guys are right! Those were two different engines. The black block was my previous build stock 5.3 that was forged and stroked to a 6.3L (383ci) Boost build. It was on my GMC Sierra with a single turbo.
MY BAD! I compiled images from a WhatsApp chat between me and the shop and failed to realize the dates as well as the differences in the pics! lol.
I guess the question still remain,
Would you boost a 4.200 LSX block? If so, by how much? Obviously will also be running Meth.
I don't know how this happened lol but I was half asleep uploading pics. You guys are right! Those were two different engines. The black block was my previous build stock 5.3 that was forged and stroked to a 6.3L (383ci) Boost build. It was on my GMC Sierra with a single turbo.
MY BAD! I compiled images from a WhatsApp chat between me and the shop and failed to realize the dates as well as the differences in the pics! lol.
I guess the question still remain,
Would you boost a 4.200 LSX block? If so, by how much? Obviously will also be running Meth.
Or would you stay NA?
Thanks!
I'd say you'd be OK with boost, though just how much is key. I have seen the LS7 aluminum block boosted reliably to 900+ hp, so my guess is you'd be fine up to 1,100hp. Beyond that, idk. If you're going to run mile long HPDEs, that may be too much, as you'll be at WOT for a lot longer than 1/4 mile, or even 1/2 mile runs.
4.200 bore with boost 👎
Cylinder wall thickness and Core shift @ 4.200
How much boost? IDK, but Reference the statement above. Detonation would be the main problem to worry about and the block being @ 4.200 not many rebuilds nor gasket Selection using Boost. Btw on the boost reference a 4.200 bore LSX gasket.
Look at the space between the cylinder's 😏
You can add boost but ....
There was a guy on the Camaro5 forum that boosted a brand new LSx454. Boost was under 10psi with a TVS2300 on top. If memory serves, it scattered on the second pull. The General politely declined to cover it. They would warranty it n/a, but backed completely the **** out knowing it was boosted.
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LSX 454 and Boost 
