LS1 into 1990 GMC
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Teching In
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LS1 into 1990 GMC I'm new to the forum and had a question for everyone. I have a 1990 GMC C2500, 350 w/ a 700R4 tranny. I want to swap it out for an LS1 setup, and was wondering how much of a hassle it actually is. How much time do you think the swap would take for a certified mechanic to do? What does the swap involve, including wiring, computer, etc.? Anything else?
Thank you everybody for your help,
Nathan
Thank you everybody for your help,
Nathan
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Joined: Dec 2004
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From: Baltimore, MD.
It takes a bunch. The 350 & the LSx platform have very little in common.
The 700R4 transmission bolts to the rear of the block, but you'll need the appropriate flexplate, spacer, and such. Whether you need the spacer will depend upon exactly which LSx motor you put in there, some of the early LSx truck motors have a longer crank).
None of the accessories interchange. So, you'll have to have the LSx PS pump, AC compressor, & alternator, and you'll have to make all that stuff play nice with the existing hardware.
You may have frame clearance issues (specifically AC Compressor)
The engine mounts are completely different. You'll need to either adapt or fabricate new mounts for the LSx engine.
PCM & wiring harness will require big time modifications. You may in fact need the '90 PCM to run gauges & such and the LSx PCM to run the engine. I don't know for certain, however, so you'll need to do some research.
Have no idea about the exhaust. You may find that stock manifolds fit just fine. You may find that they don't. I can't say. Either way, expect to have some amount of difficulty here, just because exhaust is always a pain in the butt....
Time required? Depends upon how prepared you are, how efficient you are, and how well you overcome problems / fabricate parts / ups delivery times / etc.
'JustDreamin'
The 700R4 transmission bolts to the rear of the block, but you'll need the appropriate flexplate, spacer, and such. Whether you need the spacer will depend upon exactly which LSx motor you put in there, some of the early LSx truck motors have a longer crank).
None of the accessories interchange. So, you'll have to have the LSx PS pump, AC compressor, & alternator, and you'll have to make all that stuff play nice with the existing hardware.
You may have frame clearance issues (specifically AC Compressor)
The engine mounts are completely different. You'll need to either adapt or fabricate new mounts for the LSx engine.
PCM & wiring harness will require big time modifications. You may in fact need the '90 PCM to run gauges & such and the LSx PCM to run the engine. I don't know for certain, however, so you'll need to do some research.
Have no idea about the exhaust. You may find that stock manifolds fit just fine. You may find that they don't. I can't say. Either way, expect to have some amount of difficulty here, just because exhaust is always a pain in the butt....
Time required? Depends upon how prepared you are, how efficient you are, and how well you overcome problems / fabricate parts / ups delivery times / etc.
'JustDreamin'
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Joined: Jul 2005
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From: Beebe, Arkansas
Originally Posted by nate_88
I'm new to the forum and had a question for everyone. I have a 1990 GMC C2500, 350 w/ a 700R4 tranny. I want to swap it out for an LS1 setup, and was wondering how much of a hassle it actually is. How much time do you think the swap would take for a certified mechanic to do? What does the swap involve, including wiring, computer, etc.? Anything else?
Thank you everybody for your help,
Nathan
Thank you everybody for your help,
Nathan
