Building lsx 427 from l92 block
#1
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Ok so I'm trying to get a 427 ci on my l92 block. I know that it needs a longer stroke than the stock ls7 block but here are some questions. My goal is to get arnd 600 rwhp without any fi. This will be also use for dd and reliability is a must.
1. Can I use a stock ls7 pistons and rings for ? If not what size Pistons and rods do I need?
2. Will it be cheaper to get a full complete rotating assembly or buying individual parts?
3. How much does a machine shop usually charge to bore, hone , balancing ect ect?
Thanks
1. Can I use a stock ls7 pistons and rings for ? If not what size Pistons and rods do I need?
2. Will it be cheaper to get a full complete rotating assembly or buying individual parts?
3. How much does a machine shop usually charge to bore, hone , balancing ect ect?
Thanks
#2
TECH Veteran
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Reliability is all in the valvetrain!! Don't buy LS7 lifters and expect to have a top notch reliable motor. What heads is you looking into? I believe a 427 is achievable but it'll live longer as a 416 Ci motor......
I may be wrong but I believe you'll need a 4.100 stroke for a 427ci motor.
I wouldn't do more than a 4.000 stroke with a motor that's go see a lot of street miles. The 4.000 stroke will keep the pistons in your sleeves better than a 4.100 stroke that would pull the piston out the bottom of the bore further. Sure cubes are fun but they not EVERYTHING..... A good set of heads with a great cam to match is what you really need to help dial in your horsepower goals.
I may be wrong but I believe you'll need a 4.100 stroke for a 427ci motor.
I wouldn't do more than a 4.000 stroke with a motor that's go see a lot of street miles. The 4.000 stroke will keep the pistons in your sleeves better than a 4.100 stroke that would pull the piston out the bottom of the bore further. Sure cubes are fun but they not EVERYTHING..... A good set of heads with a great cam to match is what you really need to help dial in your horsepower goals.
#3
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Ok so I'm trying to get a 427 ci on my l92 block. I know that it needs a longer stroke than the stock ls7 block but here are some questions. My goal is to get arnd 600 rwhp without any fi. This will be also use for dd and reliability is a must.
1. Can I use a stock ls7 pistons and rings for ? If not what size Pistons and rods do I need?
2. Will it be cheaper to get a full complete rotating assembly or buying individual parts?
3. How much does a machine shop usually charge to bore, hone , balancing ect ect?
Thanks
1. Can I use a stock ls7 pistons and rings for ? If not what size Pistons and rods do I need?
2. Will it be cheaper to get a full complete rotating assembly or buying individual parts?
3. How much does a machine shop usually charge to bore, hone , balancing ect ect?
Thanks
We can make your L92 a 427 LS7 it will make between 590-620RWHP on motor.
You can make 550-575(camshaft/compression dependent) with a 416 with our CNC L92's.
1. The LS7 piston and ring would fit if you Sleeve the block. LS7 4.125"
We run max bore at 4.070" on LS3's.
2. It is always best to have a professional shop assemble something like this. Your talking about making 700+ HP
3. Depends on the shops level of equipment and knowledge.
We specialize in what you are looking for.
Turn your LS2/LS3 into a Stage III LS7-LSX
Here is an example of a recent customer build taking a LS2 block and sleeving it to push the bore to 4.130. This package allows an LS2 car to be morphed into a pumped up LS7 and still retain the compatibility with the stock LS2 base engine.
This package is based around a custom sleeved LS2 block that Livernois Motorsports machines in house on its own 4-Axis CNC machine. This allows absolute precision and ensures the block is held to within just +/- .0001 to the specification.
Once the block machine work is done we utilize our own custom rotating assembly, complete with forged H-beam connected rods, forged custom pistons, stainless steel top ring and napier second, upgraded thick wall wristpin and forged stroker crankshaft. This takes us to a 429 cubic inch size.
The shortlock is then complimented with LSX-LS7 heads utilizing our own custom CNC program and valvejob, along with the FAST composite intake. This package is designed for the ultimate in streetable performance from a large cubic inch LS base. The added cubic inches and breathing from the bigger bore, coupled with the longer stroke and high flowing cylinder head matched with custom camshaft really turn this engine into a beast.
Shortblock, Longblock and Complete engine packages just like this are available to retrofit your LS2 and LS3 equipped car into a big-bore stroker LS7 monster with direct bolt-in capability.
Take a look at this earlier post it has some images
https://ls1tech.com/forums/general-l...i-ls7-lsx.html
#4
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Ok so I'm trying to get a 427 ci on my l92 block. I know that it needs a longer stroke than the stock ls7 block but here are some questions. My goal is to get arnd 600 rwhp without any fi. This will be also use for dd and reliability is a must.
1. Can I use a stock ls7 pistons and rings for ? If not what size Pistons and rods do I need?
2. Will it be cheaper to get a full complete rotating assembly or buying individual parts?
3. How much does a machine shop usually charge to bore, hone , balancing ect ect?
Thanks
1. Can I use a stock ls7 pistons and rings for ? If not what size Pistons and rods do I need?
2. Will it be cheaper to get a full complete rotating assembly or buying individual parts?
3. How much does a machine shop usually charge to bore, hone , balancing ect ect?
Thanks
#5
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Reliability is all in the valvetrain!! Don't buy LS7 lifters and expect to have a top notch reliable motor. What heads is you looking into? I believe a 427 is achievable but it'll live longer as a 416 Ci motor......
I may be wrong but I believe you'll need a 4.100 stroke for a 427ci motor.
I wouldn't do more than a 4.000 stroke with a motor that's go see a lot of street miles. The 4.000 stroke will keep the pistons in your sleeves better than a 4.100 stroke that would pull the piston out the bottom of the bore further. Sure cubes are fun but they not EVERYTHING..... A good set of heads with a great cam to match is what you really need to help dial in your horsepower goals.
I may be wrong but I believe you'll need a 4.100 stroke for a 427ci motor.
I wouldn't do more than a 4.000 stroke with a motor that's go see a lot of street miles. The 4.000 stroke will keep the pistons in your sleeves better than a 4.100 stroke that would pull the piston out the bottom of the bore further. Sure cubes are fun but they not EVERYTHING..... A good set of heads with a great cam to match is what you really need to help dial in your horsepower goals.
#6
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
Reliability is all in the valvetrain!! Don't buy LS7 lifters and expect to have a top notch reliable motor. What heads is you looking into? I believe a 427 is achievable but it'll live longer as a 416 Ci motor......
I may be wrong but I believe you'll need a 4.100 stroke for a 427ci motor.
I wouldn't do more than a 4.000 stroke with a motor that's go see a lot of street miles. The 4.000 stroke will keep the pistons in your sleeves better than a 4.100 stroke that would pull the piston out the bottom of the bore further. Sure cubes are fun but they not EVERYTHING..... A good set of heads with a great cam to match is what you really need to help dial in your horsepower goals.
I may be wrong but I believe you'll need a 4.100 stroke for a 427ci motor.
I wouldn't do more than a 4.000 stroke with a motor that's go see a lot of street miles. The 4.000 stroke will keep the pistons in your sleeves better than a 4.100 stroke that would pull the piston out the bottom of the bore further. Sure cubes are fun but they not EVERYTHING..... A good set of heads with a great cam to match is what you really need to help dial in your horsepower goals.
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#8
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I would do a K1 rods.... or a callies compstar rods. 3500 top??? Do you mean as that as far as your top end goes ? A L92/LS3 head can get you there..... I recommend having the exhaust ports ported!! I recommend that big time. It helps those heads a lot. Also use the LS3 valves if you not already using those. The valves are lighter than the L92 valves. Morel link bar lifters are go be the way to go over a drop in replacement lifter. The link bar lifters are more stable at a higher rpm than the drop in replacement lifters!! On the rocker arms be sure to upgrade those with a trunion kit.... The kit btr offers is nice. Now let's move on to the cam specs... that's all go depends on weight, gears, transmission etc.... just make sure the cam is what you really pay attention to. The camshaft for a rectangular headed motor is so CRITICAL. The specs can literally make or break the whole motor. I have seen these motors run like a bat out of hell and others run like a turtle... WHY? cause someone didn't really know what they was doing as far as cam specs go....
#9
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#10
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$3500 for a short block? Just a brief search and I found this. http://www.texas-speed.com/p-1020-ts...-assembly.aspx
That's a good buy there!! I just wouldn't use nothing at all from Eagle....
#11
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$3500 for a short block? Just a brief search and I found this. http://www.texas-speed.com/p-1020-ts...-assembly.aspx
I already have the short block. I'm talking any getting the rotating assemblies ect ect and machine work.
#14
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Even though the OP and I have discussed his build i will post up to hopefully dispell the myths posted here. We personally have more than one customer with ls3/427s that have 30k miles or more on them. One i know personally. His ls3/427 makes 600 at the tire and he daily drives it. It has over 30k on the engine now. Zero issues. Respouting internet myths or heresay does no good for the entire auto enthusiast crowd. If you want proof we can have a few post up, but come on...you guys dont think engine design and component design hasnt come a long way since even the lt1s or ls1s were new?
#15
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Even though the OP and I have discussed his build i will post up to hopefully dispell the myths posted here. We personally have more than one customer with ls3/427s that have 30k miles or more on them. One i know personally. His ls3/427 makes 600 at the tire and he daily drives it. It has over 30k on the engine now. Zero issues. Respouting internet myths or heresay does no good for the entire auto enthusiast crowd. If you want proof we can have a few post up, but come on...you guys dont think engine design and component design hasnt come a long way since even the lt1s or ls1s were new?
#16
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i myself am building a ls3/427 now , it has a callies 4.125 crank , 6.125 rods and 4.070 pistons . i plan on winding it up witha set of livernois ported l92 castings with spray on top .
#17
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From what I've learnt, the ls3 427 can be done but it is not advisable if someone plans to go for fi on the future. Meanwhile people is saying that 416 ci is way better for turbo application. As far as daily driver goes , I don't see why it's an issue.
Lmk how much you ended up spending at the machine shop.
Lmk how much you ended up spending at the machine shop.
#18
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I would have no issue with boost on a 427 ls3. But i would limit the boost of course.
As far as the other post with a 4.125 crank and a 4.070 piston...thats not a 427. That is larger.
There are many reasons the aftermarket LS pistons have a .927 pin. Can anyone guess them?
As far as the other post with a 4.125 crank and a 4.070 piston...thats not a 427. That is larger.
There are many reasons the aftermarket LS pistons have a .927 pin. Can anyone guess them?
#19
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I would have no issue with boost on a 427 ls3. But i would limit the boost of course.
As far as the other post with a 4.125 crank and a 4.070 piston...thats not a 427. That is larger.
There are many reasons the aftermarket LS pistons have a .927 pin. Can anyone guess them?
As far as the other post with a 4.125 crank and a 4.070 piston...thats not a 427. That is larger.
There are many reasons the aftermarket LS pistons have a .927 pin. Can anyone guess them?
#20
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I would not run over 10lbs honestly...but 10lbs will be alot different on stock heads vs 10lbs on say a trick flow head (assuming we are strictly comparing ls3 heads). If a competent/reliable machine shop sets it up for boost then I would run it like any other boost setup. And it will be different with different cam profiles as well to a point.
The stock pin on an ls piston (besides ls9) is .944-.945. Nearly every aftermarket pin set for any stroker build is a .927. Some of that is due to rod and pin availability and ease of availability of parts and manufacturing. And some of it is due to pin placement and ring pack placement. The CH on the can be the same on 2 pistons but if one has a .945 pin and one has a .927 pin, the .927 pin piston can have more available material for piston strength and more room for a ring pack without bridging the pin hole and having to use support rails. That is extremely oversimplifying it of course but that is a short explanation.
There are so many builds out there that ARENT on tech or cf. Not everything gets put on the internet either.
The stock pin on an ls piston (besides ls9) is .944-.945. Nearly every aftermarket pin set for any stroker build is a .927. Some of that is due to rod and pin availability and ease of availability of parts and manufacturing. And some of it is due to pin placement and ring pack placement. The CH on the can be the same on 2 pistons but if one has a .945 pin and one has a .927 pin, the .927 pin piston can have more available material for piston strength and more room for a ring pack without bridging the pin hole and having to use support rails. That is extremely oversimplifying it of course but that is a short explanation.
There are so many builds out there that ARENT on tech or cf. Not everything gets put on the internet either.
Last edited by COSPEED2; 03-10-2015 at 12:04 PM.