Getting ready to "LS" swap a '90 Suburban

Chuck

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Nov 24, 2006
Messages
221
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Location
Billings, MT
Make
GMC
Model
Suburban/ Yukon XL
Year
1990/2003
Miles
270,000/ N/A
Engine
5.7L/ 6.0L
I'm getting ready to swap in a LQ 6.0L/ 4L80e from an '03 GMC Yukon XL into my '90 V1500 Suburban and I have some questions. Were can I send the Engine wiring harness ECU, transmission controller and wiring harness so it can be used in my '90. Can I use the 700r4 crossmember on the 4L80e and if not were could I get an aftermarket one to work? Can I reuse the fuel pump from the '03 in my '90? Would it fit in the '90 sending unit? Is there anything I'll need that I don't know about and what all can be reused from either trucks. Thank you
 

grcauto

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You are asking for trouble. Have you ever done a swap like this?
 

billr

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Yeah, it certainly should be possible to do the swap, assuming you don't have to worry about smog inspection; but I gotta ask what your real desire/intention is? If you just want to get a relatively fresh engine/trans, there are easier ways to do that. If you are after increased engine size or a beefier trans, then there are also easier ways to do that. too.

Or, is the prime reason for a "swap" being that the '03 stuff is available for little-to-no cost? I understand that scenario very well! To keep the project "low cost", you will need to keep the mods DIY as much as possible. That means, probably, doing the electrical harness work yourself. I think changes to the engine/trans mounting will be trivial.
 
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grcauto

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You'll need to use the modules and program them as well as all the wiring. Anything can be done but not everything is the best.
 

Chuck

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Location
Billings, MT
Yeah, it certainly should be possible to do the swap, assuming you don't have to worry about smog inspection; but I gotta ask what your real desire/intention is? If you just want to get a relatively fresh engine/trans, there are easier ways to do that. If you are after increased engine size or a beefier trans, then there are also easier ways to do that. too.

Or, is the prime reason for a "swap" being that the '03 stuff is available for little-to-no cost? I understand that scenario very well! To keep the project "low cost", you will need to keep the mods DIY as much as possible. That means, probably, doing the electrical harness work yourself. I think changes to the engine/trans mounting will be trivial.
Yes I'm getting the '03 for almost nothing from a local tow company. I thought about DIY, but I didn't want to take the chance of messing it up, so I figured you folks would possibly know a company that does them.
 

Chuck

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Messages
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Location
Billings, MT
You are asking for trouble. Have you ever done a swap like this?
No. Nothing this ambitious. The one I did that was kinda close was swapping in a TBI 454 from a '91 crewcab into a '77 crewcab. And all we had to take everything from the '90 and mount it in the '77.
 

Chuck

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Joined
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Messages
221
Points
18
Location
Billings, MT
And I'd
Yeah, it certainly should be possible to do the swap, assuming you don't have to worry about smog inspection; but I gotta ask what your real desire/intention is? If you just want to get a relatively fresh engine/trans, there are easier ways to do that. If you are after increased engine size or a beefier trans, then there are also easier ways to do that. too.

Or, is the prime reason for a "swap" being that the '03 stuff is available for little-to-no cost? I understand that scenario very well! To keep the project "low cost", you will need to keep the mods DIY as much as possible. That means, probably, doing the electrical harness work yourself. I think changes to the engine/trans mounting will be trivial.
Also the rest is for more power and better fuel economy. I live in Montana, so we have no smog inspections and I want to keep it as original as I possibly can
 

billr

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The place shown below does many LS-based swaps, I know them very well. Try contacting them. If you don't get any good response, let me know and I will "go in through the back door". Making harnesses for remote install is probably not a normal service for them.

 

Chuck

Sr. Member
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Messages
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Points
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Location
Billings, MT
That's
The place shown below does many LS-based swaps, I know them very well. Try contacting them. If you don't get any good response, let me know and I will "go in through the back door". Making harnesses for remote install is probably not a normal service for them.

Awesome! Thank you!
 
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