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Best Year Of 4.3 Chevy Engine Swap

Discussion in 'Early CJ5 and CJ6 Tech' started by Dauntless1971, Feb 17, 2018.

  1. Feb 17, 2018
    Dauntless1971

    Dauntless1971 Member

    Bend, OR
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    Is there a best or easiest year if one was to swap in the Chevy 4.3
    I found a 87 which appears to be the first vortec tbi rated at 155 hp 4800 rmp and 230#s torque at 2000
    I think in 96 the engine went OBDII so lots more sensors, wiring etc.
     
  2. Feb 17, 2018
    3b a runnin

    3b a runnin Active Member 2023 Sponsor 2022 Sponsor

    virginia
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    I think I read where Wikipedia said pre 92 had a manual fuel pump port, but done away with after that. Would have to use electric pump.
    Been kinda looking myself.
     
  3. Feb 17, 2018
    sterlclan

    sterlclan Member 2022 Sponsor

    exploring the...
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    i know that a 95 is the odd man out, one year only on ecm and wiring. its wired with obdII harness but has obdI ecm.
     
  4. Feb 17, 2018
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    The ability to run a mech fuel pump is not overrated.
     
  5. Feb 18, 2018
    wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    York, PA
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    Google 4.3 horsepower ratings. There were different ones and a corresponding engine code.......at least up until the Vortex. As I recall, the TBI units from W/T series pick ups had the higher HP rating but, you should double check that. It's been a while since I looked.

    I prefer the simplicity of TBI as I'm pretty simple myself. Other will argue for the Vortec and have a good argument. Again, there is a ton of info out there and there is more to it than HP ratings, which is about as far as I got into it.
     
  6. Feb 18, 2018
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    IIRC the '85-86 used in C, K and G series trucks had a Quadrajet carburetor (this is documented in the 90 degree Chevrolet V6 article on Wikipedia General Motors 90° V6 engine - Wikipedia ). All the rest had either TBI or MPI, so a mechanical fuel pump port would be a vestigial feature. You could run a mechanical pump as a delivery pump to an under-hood high pressure pump for the EFI, but I see no other use for such a pump with EFI. AFAIK there is no mechanical pump that can directly supply fuel to an EFI system... possibly they could be developed, but every EFI system that I know of uses an electric pump to deliver the required high pressure.
     
  7. Feb 18, 2018
    1960willyscj5

    1960willyscj5 Well-Known Member

    Mesa, Arizona
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    Diesel fuel pump, maybe?
     
  8. Feb 18, 2018
    Dauntless1971

    Dauntless1971 Member

    Bend, OR
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    Oct 22, 2004
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    I think the advantage for me would be going with a tbi model.
    If the 4.3 had a carb I would rather just run a 225 or 231.
    I read the early models 87-95 ran on 12psi fuel pump.
    Carter makes an external fuel pump that is 14-16psi.
     
  9. Feb 18, 2018
    Dauntless1971

    Dauntless1971 Member

    Bend, OR
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    [​IMG]
    Here is a way to get it done.
     
  10. Feb 18, 2018
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    Having the mech pump possibility opens up the ability to run a simple carb and pump.

    I run a TBI rated Carter on my 89 Dodge. Solid unit. Works.

    TBI and TPI both can work, and work well, but involves significant more complexity and therefore expense, when the chassis didnt have them initially.

    It depends on what you’re after.
     
  11. Feb 22, 2018
    willys59cj5

    willys59cj5 Sponsor

    Gilroy, CA
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    MPFI uses higher pump pressure 40psi and up. TBI uses anywhere from 12-25psi. My efi setup uses a mechanical pump to feed a sump box that feeds a high pressure walbro to the TBI. Several companies make sump boxes for this purpose edelbrock comes to mind.
     
  12. Feb 22, 2018
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Most '85/'86 had a provision for mechanical pump but most had an O2 feedback carb system (computer controlled carb and distributor). You could easily swap the distributor and carb for mechanical units however. The tbi engines I've owned had the cast openings for a fuel pump but were not machined for the pushrod or pump bolt holes.some even had a block off plate even though not machined for the pushrod. As usual your mileage may vary.
     
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