LS1 to TH350
Thread Starter
7th Gear
Joined: Mar 2025
Posts: 7
Likes: 0
LS1 to TH350
Dad had an LS1 lying around in his garage and told me he wasn't going to do anything with it. So I decided to take it and swap it into my 77. Everything in the car is factory stock since I worked on it as a project car with my dad. So now I'm wondering if the TH350 would work well.
Any advice would be appreciated.
Any advice would be appreciated.
Le Mans Master
Joined: Jan 2001
Posts: 6,743
Likes: 1,385
Check this out:
https://www.speedwaymotors.com/Gen-I...SABEgL1r_D_BwE
https://www.speedwaymotors.com/Gen-I...SABEgL1r_D_BwE
Dad had an LS1 lying around in his garage and told me he wasn't going to do anything with it. So I decided to take it and swap it into my 77. Everything in the car is factory stock since I worked on it as a project car with my dad. So now I'm wondering if the TH350 would work well.
Any advice would be appreciated.
Any advice would be appreciated.
Melting Slicks
Joined: Apr 2021
Posts: 2,714
Likes: 2,162
From: Minnesota
Welcome to the forum!
Yes, it will work with an adapter like the one posted above, but personally I would be looking at a 4L60E or other overdrive transmission if I were going in this deep.
What year is the LS1?
Yes, it will work with an adapter like the one posted above, but personally I would be looking at a 4L60E or other overdrive transmission if I were going in this deep.
What year is the LS1?
Race Director
Joined: Mar 2017
Posts: 11,953
Likes: 4,508
From: Virginia
The TH350 will mate up, but will not be fun to drive.
If you can swing it, manual swap your car at the same time! Use a TKX 5-speed (or Tremec Magnum 6-speed) behind the LS.
Do you have the ECM and everything for a complete running engine? You may be able to reprogram it for whatever transmission you use, using HP Tuners. Do you know how it was configured, and what year?
If you can swing it, manual swap your car at the same time! Use a TKX 5-speed (or Tremec Magnum 6-speed) behind the LS.
Do you have the ECM and everything for a complete running engine? You may be able to reprogram it for whatever transmission you use, using HP Tuners. Do you know how it was configured, and what year?
Thread Starter
7th Gear
Joined: Mar 2025
Posts: 7
Likes: 0
Thread Starter
7th Gear
Joined: Mar 2025
Posts: 7
Likes: 0
The TH350 will mate up, but will not be fun to drive.
If you can swing it, manual swap your car at the same time! Use a TKX 5-speed (or Tremec Magnum 6-speed) behind the LS.
Do you have the ECM and everything for a complete running engine? You may be able to reprogram it for whatever transmission you use, using HP Tuners. Do you know how it was configured, and what year?
If you can swing it, manual swap your car at the same time! Use a TKX 5-speed (or Tremec Magnum 6-speed) behind the LS.
Do you have the ECM and everything for a complete running engine? You may be able to reprogram it for whatever transmission you use, using HP Tuners. Do you know how it was configured, and what year?
Melting Slicks
Joined: Apr 2021
Posts: 2,714
Likes: 2,162
From: Minnesota
The 700R4 would work and there are people that mate them to LS engines, but again, you would have to use an adapter. If you want to stick with an automatic I would go with the electronically controlled one that allows you to easily change your shift points and torque converter lockup.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Race Director
Joined: Mar 2017
Posts: 11,953
Likes: 4,508
From: Virginia
You could find a 2004 ECM that originally came with a 4L60e. You might not need to do anything (or not much, at least). Do you have an electric throttle body, and a pedal to control it? It might be worth programming that out, too.
Or, if money is no object, the Holley Terminator X Max will control the 4L60e, too.
If that LS1 came from a Corvette, there'd be a VIN stamped on it. I'm not sure about other cars.
Or, if money is no object, the Holley Terminator X Max will control the 4L60e, too.
If that LS1 came from a Corvette, there'd be a VIN stamped on it. I'm not sure about other cars.
Thread Starter
7th Gear
Joined: Mar 2025
Posts: 7
Likes: 0
You could find a 2004 ECM that originally came with a 4L60e. You might not need to do anything (or not much, at least). Do you have an electric throttle body, and a pedal to control it? It might be worth programming that out, too.
Or, if money is no object, the Holley Terminator X Max will control the 4L60e, too.
If that LS1 came from a Corvette, there'd be a VIN stamped on it. I'm not sure about other cars.
Or, if money is no object, the Holley Terminator X Max will control the 4L60e, too.
If that LS1 came from a Corvette, there'd be a VIN stamped on it. I'm not sure about other cars.
I was planning on buying a Terminator after getting the ECM but didn't know what I needed for it to work properly because it asks for like 5 things.
Thread Starter
7th Gear
Joined: Mar 2025
Posts: 7
Likes: 0
The only reason I ask is because the early LS1s have oil gallery issues that would cause overheating issues. It sounds like you have a good one though.
The 700R4 would work and there are people that mate them to LS engines, but again, you would have to use an adapter. If you want to stick with an automatic I would go with the electronically controlled one that allows you to easily change your shift points and torque converter lockup.
The 700R4 would work and there are people that mate them to LS engines, but again, you would have to use an adapter. If you want to stick with an automatic I would go with the electronically controlled one that allows you to easily change your shift points and torque converter lockup.
Melting Slicks
Joined: Sep 2010
Posts: 3,312
Likes: 697
So if your LS is a 2004 of some sort (4.8, 5.3, 6.0) what intake is on the engine? A Camaro/Corvette or truck intake?
No need to go DBW. DBC will work well and can be a bit cheaper.
I would buy the ECM and harness from one of our suppliers on this web site. I like and use Speartech and Howell. They can supply a base tune to get your project running.
With a 4l60E you can set the shift points. Also set the OD and lock up shift points.
No need to go DBW. DBC will work well and can be a bit cheaper.
I would buy the ECM and harness from one of our suppliers on this web site. I like and use Speartech and Howell. They can supply a base tune to get your project running.
With a 4l60E you can set the shift points. Also set the OD and lock up shift points.
Race Director
Joined: Mar 2017
Posts: 11,953
Likes: 4,508
From: Virginia
If you don't have the pedal, DBW DBC is likely easier (I have the pedal, and I'm still using DBC). The Terminator X replaces the ECU (and likely comes with a wiring harness). Or, if you have the wiring sorted, just do what @71 Vert LS1 recommended, and get an ECU with a tune. Or get a copy of HP Tuners, and DIY.
I think only the Terminator X Max, or the (retuned) GM ECU, will work with the 4L60e (or boost), if that's the way you go. The slightly cheaper Terminator X (non-max) will work with a manual transmission.
I think only the Terminator X Max, or the (retuned) GM ECU, will work with the 4L60e (or boost), if that's the way you go. The slightly cheaper Terminator X (non-max) will work with a manual transmission.
Last edited by Bikespace; Mar 20, 2025 at 05:37 PM.
Thread Starter
7th Gear
Joined: Mar 2025
Posts: 7
Likes: 0
So if your LS is a 2004 of some sort (4.8, 5.3, 6.0) what intake is on the engine? A Camaro/Corvette or truck intake?
No need to go DBW. DBC will work well and can be a bit cheaper.
I would buy the ECM and harness from one of our suppliers on this web site. I like and use Speartech and Howell. They can supply a base tune to get your project running.
With a 4l60E you can set the shift points. Also set the OD and lock up shift points.
No need to go DBW. DBC will work well and can be a bit cheaper.
I would buy the ECM and harness from one of our suppliers on this web site. I like and use Speartech and Howell. They can supply a base tune to get your project running.
With a 4l60E you can set the shift points. Also set the OD and lock up shift points.
It doesn't have the trunk intake, even if it did I would've changed it.
I will probably just try to find a 4l60E if everyone is insisting. It sounds like having it will give me more programmability with either the Terminator X or tune ECM routes.
Know any common cars that the 4l60E comes out of?
Thread Starter
7th Gear
Joined: Mar 2025
Posts: 7
Likes: 0
If you don't have the pedal, DBW is likely easier (I have the pedal, and I'm still using DBW). The Terminator X replaces the ECU (and likely comes with a wiring harness). Or, if you have the wiring sorted, just do what @71 Vert LS1 recommended, and get an ECU with a tune. Or get a copy of HP Tuners, and DIY.
I think only the Terminator X Max, or the (retuned) GM ECU, will work with the 4L60e, if that's the way you go. The slightly cheaper Terminator X will work with a manual transmission.
I think only the Terminator X Max, or the (retuned) GM ECU, will work with the 4L60e, if that's the way you go. The slightly cheaper Terminator X will work with a manual transmission.
Ya, I just don't know which to do because I also want to keep the original gauges, and gauge cluster, and have it function reading to temps and all that. So I don't know if it'll be easier to either the Terminator X or Tuned ECU or just forget trying to make the original gauges work with the LS.
Race Director
Joined: Mar 2017
Posts: 11,953
Likes: 4,508
From: Virginia
Sorry for the late reply.
Ya, I just don't know which to do because I also want to keep the original gauges, and gauge cluster, and have it function reading to temps and all that. So I don't know if it'll be easier to either the Terminator X or Tuned ECU or just forget trying to make the original gauges work with the LS.
Ya, I just don't know which to do because I also want to keep the original gauges, and gauge cluster, and have it function reading to temps and all that. So I don't know if it'll be easier to either the Terminator X or Tuned ECU or just forget trying to make the original gauges work with the LS.
There are some creative ways to keep your current gauges. You can find 4L60e transmissions all over Facebook. They are in a LOT of Silverados, Tahoes, Sierras, and Yukons. And they blow up a lot, too, when abused.
Melting Slicks
Joined: Apr 2021
Posts: 2,714
Likes: 2,162
From: Minnesota
I would look into additional trans cooling if you plan on putting more power to it down the road.
Melting Slicks
Joined: Sep 2010
Posts: 3,312
Likes: 697
So a basic LS1 of some type? A well built 4L60E will be fine. Maybe a Yank or Circle 2800 billet converter? Yes on the aux trans cooler. I like the B&M stacked plater cooler. -6 SS lines to and from the trans. On my 71 C3 LS swap I used all Auto Meter gauges.
Melting Slicks
Joined: Jul 2019
Posts: 2,297
Likes: 2,016
From: MA/NH Seacoast
I have several LS swapped vehicles running TH350s and TH400s. They bolt right up, just use the GM spacer that'll support the snout on the torque converter. They drive awesome, are simple and compact, and keeps everything in place where you can use the original driveshaft.
I usually clock a few thousand miles on each setup every year, including a lot of highway miles. Unless you're running a real steep rear gear, they're totally fine on the highway.
I usually clock a few thousand miles on each setup every year, including a lot of highway miles. Unless you're running a real steep rear gear, they're totally fine on the highway.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Don't do it. While you have it all loose, mate an overdrive transmission to the LS1... 700R4 or 200-4R will do the job. If the engine is "powered up", you will have to beef-up the 350 or the O/D units. If it is a stock engine configuration, any of those stock transmission will do well -- but the O'D unit will be more practical and more economical, in the long run. It will resell MUCH better, also.