LS4 swap...
Thread Starter
Joined: Dec 2006
Posts: 1,160
Likes: 30
From: New Port Richey, FL
LS4 swap... My bro-in-law has a 98 w-body with s/c 3.8L in it, but want more power... Is the 5.3 a direct swap? Has anyone done that before?
Thanks in advance
Thanks in advance
On The Tree
Joined: Dec 2010
Posts: 109
Likes: 1
I don't know if the engine cradle is the same or not, nor do I know if it has been done.
That being said, IMHO, I would recommend a turbo kit for the 3.8L vs. converting to the LS4. You can make very VERY good power with a turbo 3800.
That being said, IMHO, I would recommend a turbo kit for the 3.8L vs. converting to the LS4. You can make very VERY good power with a turbo 3800.
On The Tree
Joined: Jan 2011
Posts: 104
Likes: 0
From: Fort Leavenworth, Kansas
It's been done on a 2001 at least. I am not sure if it's the same body style/engine cradle as the '98 though.
http://montecarloforum.com/forum/six...per-ls4-26283/
http://montecarloforum.com/forum/six...per-ls4-26283/
Staging Lane
Joined: May 2011
Posts: 96
Likes: 0
Here are some thoughts to consider
How much are you going to spend on a swap vs. buying a newer car that already has the LS4? Have you priced the cars with the LS4? They're not that expensive compared to trying to fix up an older car. I realize some people want to be different, and if you have the skill and the funds....have at it.
Say you spend at LEAST 3k doing a swap. Sure you could probably bolt the LS4 to the exsisting trans, but how long will it last? The LS4 came with a up 4t60EHD, how long will that (probably older) 4T60E last? So now you need a transmission. To boot, it sounds like the factory 4T60EHD wasn't so hot so you need to buy one aftermarket. Now that trans is going to cost more than a used motor. Also consider wiring up the V8 harness into the factory electronics, and now you have to deal with the speedo, trans control, etc etc. Don't forget cooling. While probably not a big issue, you might have to find a thicker core radiator if one is available for that car.
As for aftermarket support, I completely disagree with David, you're going to find way more support for the LSx family than the 3.8 engine. Cams, intake, computer, harnesses, etc etc are readily available for the LS family. Disabling the DOD would greatly simplify support, and isn't that difficult. VS. the 3.8....sure there is support with the supercharged model (which at this point is probably your best option), but you'll pay just as much because the support is less common. I'm not saying it can't be done, but if you have to ask, then you probably don't have the knowledge yet to see the swap through.
So now that my memory was jogged, I would see if there's a 3.8L supercharged version of your engine. Likely the harness and ECU will be almost exactly the same, and buy an aftermarket beefed up trans. Usually the SS models or the Buicks had superchargers.
Good Luck.
How much are you going to spend on a swap vs. buying a newer car that already has the LS4? Have you priced the cars with the LS4? They're not that expensive compared to trying to fix up an older car. I realize some people want to be different, and if you have the skill and the funds....have at it.
Say you spend at LEAST 3k doing a swap. Sure you could probably bolt the LS4 to the exsisting trans, but how long will it last? The LS4 came with a up 4t60EHD, how long will that (probably older) 4T60E last? So now you need a transmission. To boot, it sounds like the factory 4T60EHD wasn't so hot so you need to buy one aftermarket. Now that trans is going to cost more than a used motor. Also consider wiring up the V8 harness into the factory electronics, and now you have to deal with the speedo, trans control, etc etc. Don't forget cooling. While probably not a big issue, you might have to find a thicker core radiator if one is available for that car.
As for aftermarket support, I completely disagree with David, you're going to find way more support for the LSx family than the 3.8 engine. Cams, intake, computer, harnesses, etc etc are readily available for the LS family. Disabling the DOD would greatly simplify support, and isn't that difficult. VS. the 3.8....sure there is support with the supercharged model (which at this point is probably your best option), but you'll pay just as much because the support is less common. I'm not saying it can't be done, but if you have to ask, then you probably don't have the knowledge yet to see the swap through.
So now that my memory was jogged, I would see if there's a 3.8L supercharged version of your engine. Likely the harness and ECU will be almost exactly the same, and buy an aftermarket beefed up trans. Usually the SS models or the Buicks had superchargers.
Good Luck.
Trending Topics
Thread Starter
Joined: Dec 2006
Posts: 1,160
Likes: 30
From: New Port Richey, FL
Here are some thoughts to consider
How much are you going to spend on a swap vs. buying a newer car that already has the LS4? Have you priced the cars with the LS4? They're not that expensive compared to trying to fix up an older car. I realize some people want to be different, and if you have the skill and the funds....have at it.
Say you spend at LEAST 3k doing a swap. Sure you could probably bolt the LS4 to the exsisting trans, but how long will it last? The LS4 came with a up 4t60EHD, how long will that (probably older) 4T60E last? So now you need a transmission. To boot, it sounds like the factory 4T60EHD wasn't so hot so you need to buy one aftermarket. Now that trans is going to cost more than a used motor. Also consider wiring up the V8 harness into the factory electronics, and now you have to deal with the speedo, trans control, etc etc. Don't forget cooling. While probably not a big issue, you might have to find a thicker core radiator if one is available for that car.
As for aftermarket support, I completely disagree with David, you're going to find way more support for the LSx family than the 3.8 engine. Cams, intake, computer, harnesses, etc etc are readily available for the LS family. Disabling the DOD would greatly simplify support, and isn't that difficult. VS. the 3.8....sure there is support with the supercharged model (which at this point is probably your best option), but you'll pay just as much because the support is less common. I'm not saying it can't be done, but if you have to ask, then you probably don't have the knowledge yet to see the swap through.
So now that my memory was jogged, I would see if there's a 3.8L supercharged version of your engine. Likely the harness and ECU will be almost exactly the same, and buy an aftermarket beefed up trans. Usually the SS models or the Buicks had superchargers.
Good Luck.
How much are you going to spend on a swap vs. buying a newer car that already has the LS4? Have you priced the cars with the LS4? They're not that expensive compared to trying to fix up an older car. I realize some people want to be different, and if you have the skill and the funds....have at it.
Say you spend at LEAST 3k doing a swap. Sure you could probably bolt the LS4 to the exsisting trans, but how long will it last? The LS4 came with a up 4t60EHD, how long will that (probably older) 4T60E last? So now you need a transmission. To boot, it sounds like the factory 4T60EHD wasn't so hot so you need to buy one aftermarket. Now that trans is going to cost more than a used motor. Also consider wiring up the V8 harness into the factory electronics, and now you have to deal with the speedo, trans control, etc etc. Don't forget cooling. While probably not a big issue, you might have to find a thicker core radiator if one is available for that car.
As for aftermarket support, I completely disagree with David, you're going to find way more support for the LSx family than the 3.8 engine. Cams, intake, computer, harnesses, etc etc are readily available for the LS family. Disabling the DOD would greatly simplify support, and isn't that difficult. VS. the 3.8....sure there is support with the supercharged model (which at this point is probably your best option), but you'll pay just as much because the support is less common. I'm not saying it can't be done, but if you have to ask, then you probably don't have the knowledge yet to see the swap through.
So now that my memory was jogged, I would see if there's a 3.8L supercharged version of your engine. Likely the harness and ECU will be almost exactly the same, and buy an aftermarket beefed up trans. Usually the SS models or the Buicks had superchargers.
Good Luck.
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Verdad Gallardo Staging Lane
Joined: May 2011
Posts: 96
Likes: 0
Ah Ha! Yeah those details help out. So yeah, I'm sure it could be done and the link that MillermonteSS left is probably your best guide. Those are pretty nice cars inside too. Maybe you guys should get ahold of that builder and hit him up for more details. My guess is the wiring is going to be the biggest chore. Considering what he paid for parts...I would recommend finding a yard that has a whole wrecked car. Even if it's in a different part of the country and ship it to you. That will save you nickel and diming, and whole systems can be integrated vs. piece by piece.
Again, good luck.
Again, good luck.
Teching In
Joined: Jun 2012
Posts: 2
Likes: 0
Maybe we can help each other out. I have a 1997 Monte Z34 that has the stubborn 3.4 DOHC in it. I had budgeted and began the setup for a turbo install similar to 3.4Fiero's project: http://www.gminsidenews.com/forums/f...72/index3.html I started with the exhaust full 3" mandrel bend, cat delete, 3" resonator, and 2.5" y-split into dual Flowmaster 50 Series SS muffs. After the exhaust was welded I turned the key and, to my utter disappointment, I discovered that I just created a rice burning fart can. After about a $600 investment in exhaust, a $1000 in the body kit, and another $700 for the hood, I figured my only other option would be to stuff the 5.3 LS4 in it.
I haven't seen it done yet but I have been researching for a few weeks now and am serious about doing it. I believe the best way to go about this would be to purchase the entire drive train and at least the harnesses for it. The transmission is a necessary buy because it is a beefed up 4t65e-HD (which I don't have the HD version) and the starter motor mounts to the transmission instead of the block (you would have to do extreme mods to your orig 4t65e non-HD trans to have this work) My concerns are really only that of the ECM. I don't want the DOD at all so I really don't even need the LS4 ECM. I believe any 1999 - 2002 5.3L ECM would do as long as I convert the LS4 TB from drive-by-wire to drive-by-cable (not hard to do). This would eliminate the need for the pedal from the donor car and most 99-02 5.3L are cable driven.
My questions are:
Can I use my stock PCM to control the trans (my orig trans and the LS4 are both 4t65e base trans)?
Can I configure the ECM to use my stock 97 instrument cluster?
Can the LS4 engine harness connect with a different 99-02 5.3L ECM?
I haven't seen it done yet but I have been researching for a few weeks now and am serious about doing it. I believe the best way to go about this would be to purchase the entire drive train and at least the harnesses for it. The transmission is a necessary buy because it is a beefed up 4t65e-HD (which I don't have the HD version) and the starter motor mounts to the transmission instead of the block (you would have to do extreme mods to your orig 4t65e non-HD trans to have this work) My concerns are really only that of the ECM. I don't want the DOD at all so I really don't even need the LS4 ECM. I believe any 1999 - 2002 5.3L ECM would do as long as I convert the LS4 TB from drive-by-wire to drive-by-cable (not hard to do). This would eliminate the need for the pedal from the donor car and most 99-02 5.3L are cable driven.
My questions are:
Can I use my stock PCM to control the trans (my orig trans and the LS4 are both 4t65e base trans)?
Can I configure the ECM to use my stock 97 instrument cluster?
Can the LS4 engine harness connect with a different 99-02 5.3L ECM?
Teching In
Joined: Jun 2012
Posts: 41
Likes: 2
From: London, ON
i'd stick with the 3.8 S/C engine, take the snout off the S/C, port the case, put a blockoff plate (or better yet, get an L26 Intake), get a turbo kit (used could save you a bit of money, i just seen a used CT kit go for $1700, most are in the $2000-$3000 range (used) and get that installed, rebuild the tranny and add some performance components while your in there,
my friend use to have this set up before he sold the car and it ran 11.19 in the 1/4, the new owner got it re-tuned and is now running 10.14 at the track (both times are on M/T Drag slicks)
if you go twin turbo 3.8, you could be in the 9's
that really is the best way to go, i haven't heard yet of a LS4 engine that has been modded to run sub 11's
good luck with your build, let us know what your brother-in-law does
my friend use to have this set up before he sold the car and it ran 11.19 in the 1/4, the new owner got it re-tuned and is now running 10.14 at the track (both times are on M/T Drag slicks)
if you go twin turbo 3.8, you could be in the 9's
that really is the best way to go, i haven't heard yet of a LS4 engine that has been modded to run sub 11's
good luck with your build, let us know what your brother-in-law does
TECH Apprentice
Joined: Dec 2010
Posts: 383
Likes: 1
Here are some thoughts to consider
How much are you going to spend on a swap vs. buying a newer car that already has the LS4? Have you priced the cars with the LS4? They're not that expensive compared to trying to fix up an older car. I realize some people want to be different, and if you have the skill and the funds....have at it.
Say you spend at LEAST 3k doing a swap. Sure you could probably bolt the LS4 to the exsisting trans, but how long will it last? The LS4 came with a up 4t60EHD, how long will that (probably older) 4T60E last? So now you need a transmission. To boot, it sounds like the factory 4T60EHD wasn't so hot so you need to buy one aftermarket. Now that trans is going to cost more than a used motor. Also consider wiring up the V8 harness into the factory electronics, and now you have to deal with the speedo, trans control, etc etc. Don't forget cooling. While probably not a big issue, you might have to find a thicker core radiator if one is available for that car.
As for aftermarket support, I completely disagree with David, you're going to find way more support for the LSx family than the 3.8 engine. Cams, intake, computer, harnesses, etc etc are readily available for the LS family. Disabling the DOD would greatly simplify support, and isn't that difficult. VS. the 3.8....sure there is support with the supercharged model (which at this point is probably your best option), but you'll pay just as much because the support is less common. I'm not saying it can't be done, but if you have to ask, then you probably don't have the knowledge yet to see the swap through.
So now that my memory was jogged, I would see if there's a 3.8L supercharged version of your engine. Likely the harness and ECU will be almost exactly the same, and buy an aftermarket beefed up trans. Usually the SS models or the Buicks had superchargers.
Good Luck.
How much are you going to spend on a swap vs. buying a newer car that already has the LS4? Have you priced the cars with the LS4? They're not that expensive compared to trying to fix up an older car. I realize some people want to be different, and if you have the skill and the funds....have at it.
Say you spend at LEAST 3k doing a swap. Sure you could probably bolt the LS4 to the exsisting trans, but how long will it last? The LS4 came with a up 4t60EHD, how long will that (probably older) 4T60E last? So now you need a transmission. To boot, it sounds like the factory 4T60EHD wasn't so hot so you need to buy one aftermarket. Now that trans is going to cost more than a used motor. Also consider wiring up the V8 harness into the factory electronics, and now you have to deal with the speedo, trans control, etc etc. Don't forget cooling. While probably not a big issue, you might have to find a thicker core radiator if one is available for that car.
As for aftermarket support, I completely disagree with David, you're going to find way more support for the LSx family than the 3.8 engine. Cams, intake, computer, harnesses, etc etc are readily available for the LS family. Disabling the DOD would greatly simplify support, and isn't that difficult. VS. the 3.8....sure there is support with the supercharged model (which at this point is probably your best option), but you'll pay just as much because the support is less common. I'm not saying it can't be done, but if you have to ask, then you probably don't have the knowledge yet to see the swap through.
So now that my memory was jogged, I would see if there's a 3.8L supercharged version of your engine. Likely the harness and ECU will be almost exactly the same, and buy an aftermarket beefed up trans. Usually the SS models or the Buicks had superchargers.
Good Luck.
B) The op said he has a s/c 3.8l already
C) David knows exaactly what is available for aftermarket support for these cars.
As do I. I own both the LS4 , and the 3.8S/C , i am here to say that the humble 3.8 has a vastly superior aftermarket. While you have more options for heads , and cams for the ls4 , that is about it. If you want to make 400+whp , the 3.8s/c is the way to go.
OP i think you need to tell us what your long term goals with this car are. What kind of shape is the body and suspenscion in.
