LM7 swap

Discussion in 'High Tech Retrofits' started by BigBlock73, Jan 14, 2020 at 7:25 AM.

  1. BigBlock73

    BigBlock73 Veteran Member Lifetime Gold Member

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    I have a 2000 Silverado with the 5.3 engine with 60K miles.The frame is rusted.

    Thinking about swapping the engine it into my 73.Getting older and want a reliable cruiser that gets decent gas mileage.
    Been searching and can't find any specific info due to the plethora of info out there.

    Not looking to upgrade for performance,just economically minded swap.
    Want it to fit under the flat hood.

    Used parts wherever possible.
     
  2. ErikNORCAL

    ErikNORCAL Veteran Member

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    What’s the question?
    Should work, think the earlier LS motors had a different crank to flywheel/flex plate measurement. After that, 1” set back plates should put you in the same position as the sbc, at least it did on mine.
    -The truck accessory drive may sit high but at least there are a number of options these days.
    -you’ll have to think about the harness, Trans type, and future programming.
    -fuel system
     
    Last edited: Jan 14, 2020 at 9:30 AM
  3. BigBlock73

    BigBlock73 Veteran Member Lifetime Gold Member

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    Looking for recommendations from people who did the swap.
    Intake,accessory drives,oil pan,exhaust,wiring harness,computer...
    I would be using the muncie trans with 3:42 gears that are in the car.
     
  4. ErikNORCAL

    ErikNORCAL Veteran Member

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    Just opinion, biggest take away at the end of the swap was the electronics make it great. Electronics likely need a VSS signal and may affect which gauges you use. Tuning OEM electronics (ecm), May get expensive. So, an electronics/efi package that can address above and put the controls easily at your fingertips may put you ahead in the end after the initial cash outlay.
     
  5. BigBlock73

    BigBlock73 Veteran Member Lifetime Gold Member

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    Not going to be changing the trans so would have to come up with a alternate control system.

    This is the info I'm looking for.
    Thanks
    Erik
     
  6. ErikNORCAL

    ErikNORCAL Veteran Member

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    Can use GPS to feed VSS (what I’m doing), however, I can’t verify the settings in and Speedo out unless I buy one of the programs or go to a tuner. Hence, the suggestion for a package, one that lets you monitor everything and puts it at your control. Anyway, you get the point.
     
    Last edited: Jan 14, 2020 at 4:39 PM
  7. badazz81z28

    badazz81z28 Veteran Member

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    The 4 speed can operate just as it is. The stock gauges can also be used with proper adapter fittings while still using the sensors for the ECM. I run my coolant temp on the passenger side while the OE LS sensor is on the driver side. I would look for a LS1 intake manifold and car accessories or a alternator relocation kit.
    Not worth messing with a old harness. Spend the $500 on a new one ready to go. New wires and will be plug and play.
     
  8. BigBlock73

    BigBlock73 Veteran Member Lifetime Gold Member

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    Thanks badazz
    I found a relocation kit,can I reuse the alt from the truck?
    With the LS1 intake, will I need to get new,fuel rails,injectors,throttle body?
    Can I reuse the computer?
    Recommendation for a wire harness.
    Can the original tach be hooked up to the LS?
     
  9. nobreaks254

    nobreaks254 Veteran Member

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    should be able to use the truck alternator.
    I would just find a ls1 (ls6 would be a nice upgrade) with rail and injectors, truck tb will be fine.
    truck computer will be fine, will need to be flashed to remove vats, rear o2's, ect.
    PSI is popular. I personally enjoy wiring and gives you the option to route things the way you want, plus you will get educated.
    Tach im not sure about. Guessing no. Ive always used aftermarket
     
  10. BigBlock73

    BigBlock73 Veteran Member Lifetime Gold Member

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