Future LS conversion in my 87 K5

Discussion in 'The Garage' started by F-ingrob, Jun 10, 2019.

  1. F-ingrob

    F-ingrob Wheres the mud Premium Member

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    I just picked up a 2004 chevy Avalanche with a 5.3 but its 2wd so i have to find a 4wd 4L60 because my built 700R4 is not compatible
    Questions are
    • I will be removing the motor and the complete harness under the hood. Is there anything else I need besides the cat forward exhaust and gas pedal (its fly by wire)
    • what mounts have others used that worked with out moving the motor back and losing drive shaft length
    • who can flash the computer and redo the harness
    Any help is very much appreciated
    And Im doing this because all the throttle body stuff is gone and it has a carb
    Im trying to go back to being able to smog it
    And being fuel injected
     
  2. Babaganoosh

    Babaganoosh 1 ton status Premium Member GMOTM Winner

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    You can use your built 700 in the swap, or are you against it?

    Adjustable mounts will help save the shafts. A local tuner will help a lot with the swap if you can find a good one.
     
  3. F-ingrob

    F-ingrob Wheres the mud Premium Member

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    I am not against using my 700r4
    It is a stand alone with a toggle switch to lock the converter
    Also I heard the passenger exhaust manifold wont work
    Is that so
     
  4. Babaganoosh

    Babaganoosh 1 ton status Premium Member GMOTM Winner

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    The factory ls has exhaust manifolds with the collectors pointing in the wrong direction, headers are cheap now for a swap, f body headers are nice but they do have them for our years.
     
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  5. ZooMad75

    ZooMad75 1/2 ton status Premium Member GMOTM Winner

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    Using standard truck manifolds on mine with the swap/slider mounts in the stock position. Manifolds don't hit and trans stayed right where GM put it. And where it is puts the driver's side head right on the lower pinch weld on the firewall. Mine hit and required some massaging to keep from rubbing.

    As the resident nutjob running an LS with a 700r4, your choice of throttle won't work. You still have a TV cable to hook up to allow the trans to work right. Switch to a Cable throttle (will bolt right up) and you can use a kit from Bowtie Overdrives to work with the Vortec truck intake manifold. It's very complete, a little complex to set up but once it is, I've never had to go back and fool with it. That's been over three years. Your tuner can do what needs to be done to retrograde the tune for a cable throttle.

    As far as the rest of your swap questions, harness/tuner subjects have been discussed at depth all over in build threads and in the injection section. Searching will net a bucketload of results to read through. But put basically, if you are solid on automotive wiring it can be done yourself, sent off to somebody that can do it or pay to buy a harness completely new as a standalone and drop in. The budget is the limiting factor there.
     
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  6. F-ingrob

    F-ingrob Wheres the mud Premium Member

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    Thank you for the input
    I may go with a 4l60e to keep things easy
     
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  7. MetalMulishaMarcus

    MetalMulishaMarcus 1 Ton Status Premium Member

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    Out of curiosity, what year LS would work with a 700r4? Example, I have an 01 5.3 out of a Tahoe which i believe is a drive by cable, would that work with a 700r4?

    I ask because I'll eventually be going through this same swap and I keep going back and forth about what trans I want to use (700r4, 4l65e or nv4500).
     
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  8. F-ingrob

    F-ingrob Wheres the mud Premium Member

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    Yes the 700r4 will work with a drive by cable
     
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  9. diesel4me

    diesel4me 1 ton status Premium Member

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    I've read the torque converter pilot size on the crankshaft is different on LS engines,and you need an adapter to mate up an earlier automatic to one when doing an LS swap into an older GM vehicle..

    Seems like a lot of adapting needs to be done to get an LS into an older vehicle,from what I've read on some swaps online..

    This is just an example,there are several different suppliers selling these and this one may or may not be what you need for your particular application..

    LS Crankshaft TH350/TH400/700R4 Torque Converter Adapter Sleeve
     
  10. ZooMad75

    ZooMad75 1/2 ton status Premium Member GMOTM Winner

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    Any gen III can bolt the early cable throttle to the intake. But the 01 Tahoe setup is basically the same setup I used.

    I can't say if the early cable throttle would bolt up to the gen IV intake since I haven't tried it.
     
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