LS swap squarebody suburban w/tbi
06-01-2019, 02:15 PM
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LS swap squarebody suburban w/tbi Looking to swap 4.8/5.3/6.0 into a '90 suburban tbi 350/700r4
I would like to have everything working as it is now, AC, cluster. I want to use the 700r4 as well. I don't want headers.
This will be a sometimes daily driver, once completed.
My goal is reliability, simplicity and of course affordability just want a solid road trip driver.
I'm planning on buying a wrecked Craigslist vehicle, or going to the salvage yard to pick.
What I know I'll need/to do
Walbro 255 fuel pump (in stock tbi gas tank)
LS plate adapter motor mounts
Fuel pressure regulator
Flexplate
Reworked LS wiring harness (I have been watching YouTube videos and reading over lt1swap.com, I feel confident to tackle it.)
Possibly flexplate adapter as well
Fuel line adapters (using oem steel braided hoses that connect to tbi unit)
Flashed donor computer to delete vats, possibly 02 sensor if I can't use donor exhaust system.
Anything parts I'm overlooking please let me know. Thanks.
https://www.speedwaymotors.com/LS1-LS2-LS6-5-3-6-0-to-TH350-TH400-700R4-4L60-Adapter-Flexplate,60449.html
How difficult/fabrication wise is it to use the oem exhaust from the ls donor vehicle on the suburban, will it be as simple as just moving exhaust hangers.
I was told drive by cable is the simplest setup, how does that work on a 700r4 because it has a TV cable, can't find any adapters.
If I'm unable to find a donor with dbc how difficult is it to use the dbw, is it even possible with the 700r4. Can I just swap intakes with a junkyard dbc intake, will I need to swap the computer as well.
Info:
'90 suburban 350 tbi/700r4
Looking for donors between: '99-'07 4.8/5.3/6.0
I sincerely thank you for your time and advice, it is greatly appreciated.
I would like to have everything working as it is now, AC, cluster. I want to use the 700r4 as well. I don't want headers.
This will be a sometimes daily driver, once completed.
My goal is reliability, simplicity and of course affordability just want a solid road trip driver.
I'm planning on buying a wrecked Craigslist vehicle, or going to the salvage yard to pick.
What I know I'll need/to do
Walbro 255 fuel pump (in stock tbi gas tank)
LS plate adapter motor mounts
Fuel pressure regulator
Flexplate
Reworked LS wiring harness (I have been watching YouTube videos and reading over lt1swap.com, I feel confident to tackle it.)
Possibly flexplate adapter as well
Fuel line adapters (using oem steel braided hoses that connect to tbi unit)
Flashed donor computer to delete vats, possibly 02 sensor if I can't use donor exhaust system.
Anything parts I'm overlooking please let me know. Thanks.
https://www.speedwaymotors.com/LS1-LS2-LS6-5-3-6-0-to-TH350-TH400-700R4-4L60-Adapter-Flexplate,60449.html
How difficult/fabrication wise is it to use the oem exhaust from the ls donor vehicle on the suburban, will it be as simple as just moving exhaust hangers.
I was told drive by cable is the simplest setup, how does that work on a 700r4 because it has a TV cable, can't find any adapters.
If I'm unable to find a donor with dbc how difficult is it to use the dbw, is it even possible with the 700r4. Can I just swap intakes with a junkyard dbc intake, will I need to swap the computer as well.
Info:
'90 suburban 350 tbi/700r4
Looking for donors between: '99-'07 4.8/5.3/6.0
I sincerely thank you for your time and advice, it is greatly appreciated.
Last edited by Cfan10; 06-01-2019 at 02:22 PM.
06-01-2019, 03:23 PM
#2
TECH Fanatic
What state are you in? Any emissions testing required where you live? Here's what got deleted and changed in my 5.3 liter truck motor PCM:
Startup and at temp idle raised 100 rpm
PE Delay set to zero - Power Enrichment
Cat overtemp disabled
All EVAP, EGR, fuel sender, and rear O2 codes deleted
Speedo and shift points corrected for current tire/gear
Max line psi disabled in case of MAF failure
VATS turned off
Fans Activate - First fan on @ 195, second on at 210, both off at 190
My PCM is mounted over the glove box but under the dash cap.
I'd ditch the 700R4 and go with something more modern to eliminate TV adjustment problems. That will also eliminate your flexplate search problems. I'm DBC running a standard GM truck throttle cable. If you go DBW, make sure you get the matching electronic throttle pedal. Think long and hard about what you are going to do about transmission cooler lines before you stab in your modern trans. They are usually a tight fit in an older vehicle and some snipping of tin or banging with a big hammer might be required.
As far as using the donor exhaust system and manifolds, it'll all come down to you measuring things. I could not use my donor truck manifolds because they were too wide for my El Camino frame rails. But a set of Holley Hooker Blackheart headers fits perfectly and I don't think you can totally eliminate the idea of headers until you can measure things and "imagineer" yourself a solution.
Rick
Startup and at temp idle raised 100 rpm
PE Delay set to zero - Power Enrichment
Cat overtemp disabled
All EVAP, EGR, fuel sender, and rear O2 codes deleted
Speedo and shift points corrected for current tire/gear
Max line psi disabled in case of MAF failure
VATS turned off
Fans Activate - First fan on @ 195, second on at 210, both off at 190
My PCM is mounted over the glove box but under the dash cap.
I'd ditch the 700R4 and go with something more modern to eliminate TV adjustment problems. That will also eliminate your flexplate search problems. I'm DBC running a standard GM truck throttle cable. If you go DBW, make sure you get the matching electronic throttle pedal. Think long and hard about what you are going to do about transmission cooler lines before you stab in your modern trans. They are usually a tight fit in an older vehicle and some snipping of tin or banging with a big hammer might be required.
As far as using the donor exhaust system and manifolds, it'll all come down to you measuring things. I could not use my donor truck manifolds because they were too wide for my El Camino frame rails. But a set of Holley Hooker Blackheart headers fits perfectly and I don't think you can totally eliminate the idea of headers until you can measure things and "imagineer" yourself a solution.
Rick
06-01-2019, 03:26 PM
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What state are you in? Any emissions testing required where you live? Here's what got deleted and changed in my 5.3 liter truck motor PCM:
Startup and at temp idle raised 100 rpm
PE Delay set to zero - Power Enrichment
Cat overtemp disabled
All EVAP, EGR, fuel sender, and rear O2 codes deleted
Speedo and shift points corrected for current tire/gear
Max line psi disabled in case of MAF failure
VATS turned off
Fans Activate - First fan on @ 195, second on at 210, both off at 190
My PCM is mounted over the glove box but under the dash cap.
I'd ditch the 700R4 and go with something more modern to eliminate TV adjustment problems. That will also eliminate your flexplate search problems. I'm DBC running a standard GM truck throttle cable. If you go DBW, make sure you get the matching electronic throttle pedal. Think long and hard about what you are going to do about transmission cooler lines before you stab in your modern trans. They are usually a tight fit in an older vehicle and some snipping of tin or banging with a big hammer might be required.
As far as using the donor exhaust system and manifolds, it'll all come down to you measuring things. I could not use my donor truck manifolds because they were too wide for my El Camino frame rails. But a set of Holley Hooker Blackheart headers fits perfectly and I don't think you can totally eliminate the idea of headers until you can measure things and "imagineer" yourself a solution.
Rick
Startup and at temp idle raised 100 rpm
PE Delay set to zero - Power Enrichment
Cat overtemp disabled
All EVAP, EGR, fuel sender, and rear O2 codes deleted
Speedo and shift points corrected for current tire/gear
Max line psi disabled in case of MAF failure
VATS turned off
Fans Activate - First fan on @ 195, second on at 210, both off at 190
My PCM is mounted over the glove box but under the dash cap.
I'd ditch the 700R4 and go with something more modern to eliminate TV adjustment problems. That will also eliminate your flexplate search problems. I'm DBC running a standard GM truck throttle cable. If you go DBW, make sure you get the matching electronic throttle pedal. Think long and hard about what you are going to do about transmission cooler lines before you stab in your modern trans. They are usually a tight fit in an older vehicle and some snipping of tin or banging with a big hammer might be required.
As far as using the donor exhaust system and manifolds, it'll all come down to you measuring things. I could not use my donor truck manifolds because they were too wide for my El Camino frame rails. But a set of Holley Hooker Blackheart headers fits perfectly and I don't think you can totally eliminate the idea of headers until you can measure things and "imagineer" yourself a solution.
Rick
06-01-2019, 03:33 PM
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Thanks for the reply. I was going to keep the 700r4 to keep cost down and to just get it back on the road asap, didn't want modify the driveshaft. Thinking the chance of finding a donor with a good 4l60e are slim, no real way to check transmissions but checking the fluid, I have a 4l60e in my daily that fluid shows good but it slips sometimes.
06-01-2019, 04:18 PM
#5
TECH Fanatic
If you find a wrecked vehicle with an LS engine and transmission, there is a strong presumption that it was moving under its own power at the moment of the accident. Thus, the transmission is likely good. Mine only needed a new vehicle speed sensor to clear its few transmission related codes after I got it all running.
Rick
Rick
06-02-2019, 06:53 AM
#6
There are a ton of Suburban/Yukon and Tahoe 5.3's in the Houston for the picking, my suggestion is go buy a complete vehicle that you can drive and then take everything and stuff it into your square body including the drive by wire pedal, hydroboost and radiator....
06-02-2019, 11:43 AM
#7
On The Tree
On the header vs. manifold question. Truck manifolds will require some trimming of the frame rails when going into a squarebody. Trailblazer SS, 2010 camaro, and a number of other manifolds tuck closer to the block and don't require modification of the frame. I'm told the frame mods are minor, but have not seen it done myself. It might be worth trimming the frame rail in your case, if it means you can use the manifolds and cross-over pipe that came with the drivetrain.
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06-02-2019, 09:24 PM
#8
Launching!
Modify your existing harness to fit the new motor. Mount the ECM where the existing one is.
A 4l80e bolted in where my 60e was without driveshaft modification.
Probably go ahead and blow up the 700 then swap in an 80e.
I used the Transdapt motor mount plates with the 1" setback holes. Bolted right up to the stock Motor Mounts and Transmission.
I think I had to use a non-dished flexplate. Xcel Parts had all that in stock in Houston.
I used the Kwik Brackets for A/C, but now someone is making brackets that will let the A/C Compressor mount in the stock location so then the stock hoses can be used. My '96 had the A/C on the Drivers Side.
It's been so long now that I guess the Alternator was on the Passenger Side with the stock TBI.
I didn't need to change the Fuel Pump because I had the High Pressure unit already.
-KP
A 4l80e bolted in where my 60e was without driveshaft modification.
Probably go ahead and blow up the 700 then swap in an 80e.
I used the Transdapt motor mount plates with the 1" setback holes. Bolted right up to the stock Motor Mounts and Transmission.
I think I had to use a non-dished flexplate. Xcel Parts had all that in stock in Houston.
I used the Kwik Brackets for A/C, but now someone is making brackets that will let the A/C Compressor mount in the stock location so then the stock hoses can be used. My '96 had the A/C on the Drivers Side.
It's been so long now that I guess the Alternator was on the Passenger Side with the stock TBI.
I didn't need to change the Fuel Pump because I had the High Pressure unit already.
-KP