C4 Corvette LS Swap engine weight question
Thread Starter
Intermediate
Joined: May 2022
Posts: 28
Likes: 3
From: Massachusetts
C4 Corvette LS Swap engine weight question
Hello,
I’m in the process of an LS swap in my 1988 Corvette and I want to keep the 50/50 weight distribution. I saw a fully dressed L98 is 431 pounds, and an LS3 is 418 pounds. I wanted to originally do a LQ4 but that is about 520 pounds which is quite heavy! It seems the aluminum LS3 would be better for weight distribution despite the original L98 being iron with aluminum heads.
I thought the iron LQ4 6.0 would be closer in weight than the LS3. However I seem to be wrong.
If I want to keep the 50/50 weight distribution, what should I do?
Also going from a 4+3 to a magnum F T56. That transmission could change the weight as well, I can use an aluminum bellhousing to maybe change the weight, or a carbon fiber hood.
Thank you!
I’m in the process of an LS swap in my 1988 Corvette and I want to keep the 50/50 weight distribution. I saw a fully dressed L98 is 431 pounds, and an LS3 is 418 pounds. I wanted to originally do a LQ4 but that is about 520 pounds which is quite heavy! It seems the aluminum LS3 would be better for weight distribution despite the original L98 being iron with aluminum heads.
I thought the iron LQ4 6.0 would be closer in weight than the LS3. However I seem to be wrong.
If I want to keep the 50/50 weight distribution, what should I do?
Also going from a 4+3 to a magnum F T56. That transmission could change the weight as well, I can use an aluminum bellhousing to maybe change the weight, or a carbon fiber hood.
Thank you!
Last edited by TheRealDestrux; Dec 5, 2022 at 10:32 AM.
Le Mans Master
Joined: Aug 2017
Posts: 6,928
Likes: 1,486
From: New Jersey
It's not quite 50/50 on the weight distribution but it is very close. You can save a little weight on the LQ4 by dropping the manifolds and going to short headers if they fit... you can also push the engine back a little further in the car...
Then just shave weight elsewhere... move the battery to the rear and you have offset most of the gain... pull out the A/C and heat if you don't plan on using it which will also shed some weight from the LQ4 by ditching the compressor. Lighter flywheel, the transmission ends up a little further back too... I don't really think it would throw it off as much as you're thinking. Oh and LS3s are expensive...
Then just shave weight elsewhere... move the battery to the rear and you have offset most of the gain... pull out the A/C and heat if you don't plan on using it which will also shed some weight from the LQ4 by ditching the compressor. Lighter flywheel, the transmission ends up a little further back too... I don't really think it would throw it off as much as you're thinking. Oh and LS3s are expensive...
Drifting
Joined: Mar 2018
Posts: 1,360
Likes: 400
From: DFW TX
550 lbs is much closer to what an aluminum head L98 weighs fully dressed. The LQ4 is about 580 lbs. I wouldn't fret over it, you will likely drop a few lbs from different oil pan and car intake manifold. If you use a c5 or aftermarket accessory drive, it will likely be lighter as well.
The real weight savings would come from an aluminum block LS. About 80 lbs less weight.
The real weight savings would come from an aluminum block LS. About 80 lbs less weight.
Advanced
Joined: Mar 2021
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I weighed everything when I replaced my LT1 with an LS2. It was ~ 110 lbs weight reduction. That was both setups weighed on the same scales in my garage, so I trust it in general. In my case, I am running a larger 4" stroke aftermarket crank, aftermarket pistons and rods, valve springs, and a FAST intake, so I might be a few pounds headier than a stock aluminum LS.
Your numbers for a fully dressed L98 seem low.
You may be able to remove some other modules/etc from underhood. I was able to with the Lt1 swap. You might go with a smaller torque converter/lighter clutch. My Yank SS3600 is smaller and lighter than the stock converter.
You could relocate the battery to the rear passenger storage compartment also.
Your numbers for a fully dressed L98 seem low.
You may be able to remove some other modules/etc from underhood. I was able to with the Lt1 swap. You might go with a smaller torque converter/lighter clutch. My Yank SS3600 is smaller and lighter than the stock converter.
You could relocate the battery to the rear passenger storage compartment also.
Le Mans Master
Joined: Jul 2000
Posts: 7,633
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From: Greenville SC
This site states the L98 is 585.7, which seems more accurate. https://www.corvsport.com/1989-corvette-specifications/
Thread Starter
Intermediate
Joined: May 2022
Posts: 28
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From: Massachusetts
This site states the L98 is 585.7, which seems more accurate. https://www.corvsport.com/1989-corvette-specifications/
Thank you!
Last edited by TheRealDestrux; Dec 5, 2022 at 06:25 PM.
Burning Brakes
Joined: Jun 2015
Posts: 1,176
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From: Shelbyville Kentucky
Don't over think it. The C4 was not 50/50 the C5 was. The aluminum block will be about 100 lbs lighter than the iron block. You will be closer to 50/50 with the aluminum block engine.
Le Mans Master
Joined: Aug 2017
Posts: 6,928
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From: New Jersey
most C5s are closer to 51/49 than 50/50... the difference in WD is minimal between the two and isn't really that important. The whole setup of the entire car is imo much more important.
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Thread Starter
Intermediate
Joined: May 2022
Posts: 28
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From: Massachusetts
I have the rest of the car down pretty damn good. The suspension is getting completely overhauled with Van Steel parts. Massive list. Transmission I got down, ratios, rear diff ratio, driveshaft, halfshafts, splines, clutch. Pretty much everything but getting what I want from the engine is just difficult.
Le Mans Master
Joined: Aug 2017
Posts: 6,928
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From: New Jersey
I do have a setup, but I’m concerned about drivability. I got the setup from the LS1Forum. Makes the power I’m looking for but it’s possible it’s too radical for the street.
I have the rest of the car down pretty damn good. The suspension is getting completely overhauled with Van Steel parts. Massive list. Transmission I got down, ratios, rear diff ratio, driveshaft, halfshafts, splines, clutch. Pretty much everything but getting what I want from the engine is just difficult.
I have the rest of the car down pretty damn good. The suspension is getting completely overhauled with Van Steel parts. Massive list. Transmission I got down, ratios, rear diff ratio, driveshaft, halfshafts, splines, clutch. Pretty much everything but getting what I want from the engine is just difficult.
Granted a 60/40 weight distribution wouldn't be ideal but if you're not really altering it... I wouldn't think it having a major impact.
Advanced
Joined: Mar 2021
Posts: 68
Likes: 29
In my long C4 swap thread, I talk about weights and actually measure both the LT1 and LS2, and also consider all the other factors.
https://ls1tech.com/forums/conversio...nator-x-3.html
Look around post 57-58 for weights and numbers.
https://ls1tech.com/forums/conversio...nator-x-3.html
Look around post 57-58 for weights and numbers.
Thread Starter
Intermediate
Joined: May 2022
Posts: 28
Likes: 3
From: Massachusetts
In my long C4 swap thread, I talk about weights and actually measure both the LT1 and LS2, and also consider all the other factors.
https://ls1tech.com/forums/conversio...nator-x-3.html
Look around post 57-58 for weights and numbers.
https://ls1tech.com/forums/conversio...nator-x-3.html
Look around post 57-58 for weights and numbers.
Last edited by TheRealDestrux; Dec 7, 2022 at 01:51 PM.
Melting Slicks
Joined: Mar 2002
Posts: 2,873
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From: Sligo PA
I made a thread about weighing LS motors and 4L80e/4L60e transmissions awhile ago. An LQ4 is only 450 lbs.
See for yourself.
https://www.corvetteforum.com/forums...60e-4l80e.html
The only reason to be that concerned about weight balance is if you're auto crossing the car. If you are then an aluminum 5.3L is your answer. You can get more than enough power from one for auto-X and they are about 80 pounds lighter than an LQ4. They are also very low cost from a wreaking yard. Look for a early 2000's Trailblazer EXT. You should be able to grab one for around $250. But if your car is an automatic and you just want to do burn outs and have fun then you are way better off with an iron block LS like an LQ9/LQ4.
See for yourself.
https://www.corvetteforum.com/forums...60e-4l80e.html
The only reason to be that concerned about weight balance is if you're auto crossing the car. If you are then an aluminum 5.3L is your answer. You can get more than enough power from one for auto-X and they are about 80 pounds lighter than an LQ4. They are also very low cost from a wreaking yard. Look for a early 2000's Trailblazer EXT. You should be able to grab one for around $250. But if your car is an automatic and you just want to do burn outs and have fun then you are way better off with an iron block LS like an LQ9/LQ4.
Advanced
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