4.3L swap to a 5.7L

Discussion in 'Chevy C/K Truck Forum' started by DanPruski, Jan 23, 2012.

  1. DanPruski

    DanPruski Member

    I have a '93 4.3L TBI engine with a manual 5 speed tranny.
    Found a 5.7L thats carburated that i wanna swap over.
    So do i just need to get an intake manifold, TBI, air filter housing, fan shroud, and radiator off another 350. Or is there more ill need to swap around?
  2. cooter71

    cooter71 Member

    i believe that you'll need the entire TBI unit including the computer/wire harness, but i'm not sure. you definitely need the fan shroud and radiator, but seriously, if you have any problem going to a junkyard and finding one of these trucks with a 350 i don't know where you're lookin
  3. DanPruski

    DanPruski Member

    yeah, thats what i was thinking is the whole tbi unit with harness, which i can pull off a junkyard engine for fairly cheap prolly. I just wanted to know if theres anything else ill need, and any major things that will get in the way of doing it. Ive pulled some engines in my day but havent done this big of a difference with a swap, v6-v8
  4. outalne94z71

    outalne94z71 Member

    you will need a harness from a 92 or 93, 88-91 is one type harness and ecm and 92/93 is different and 94 is a change again, it was small changes but can mess you up, be best to just get a 93 harness so it would be plug and play, should not matter what trans the harness is for since you are using the manual trans right?
    you need a v8 gauge cluster too for the tach to operate properly as well.

    i would have to see your v6 harness but you may be lucky and may be able to just drop the 350 in it and change the cal pack/eprom to a v8 one
    Last edited: Jan 24, 2012
  5. DanPruski

    DanPruski Member

    so ill have to get a 93 harness from a junkward, probably the same engine i get the TB and intake manifold and what not from then to be safe since my trucks a 93, the engine is like an 89 or something i think so will that be fine with a 93 harness?
    and yeah im using the manual tranny still. And ill need a guage cluster from a 93 5.7 also?

    what do you mean the cal pack/Eprom to a v8 one?
  6. outalne94z71

    outalne94z71 Member

    the calpac/eprom is what the ecm chip is called, the earlier ones were call calpac and then later they got the name eprom and then in 96 when they went obdII the chip is not changeable but you can reprogram the whole ecm.

    the 89 as a longblock will work you just need the 93 sensors and egr solenoid , if i remember right the 93-95 sensors and egr were the same and the earlier motors had the round egr solenoid and the tps had a different plug and i think the iac wiring was a little different on earlier ones, been a long time since i had to think about it, basically if you get the tbi stuff and sensors with that 93 5.7 wiring and ecm it should be all plug and play, your fuel system to that tbi is all the same so no problem with that. what is your plan for exhaust?

    be sure when you swap the radiator that the side cutouts are open in the radiator support so the air flow can get to the whole radiator, there is a recess whey they are cut out depending on what motor/raditor they were meant for , like diesels and 454 got the whole thing opened up.
    Last edited: Jan 24, 2012
  7. DanPruski

    DanPruski Member

    Okay, that all helps out a whole lot. Thanks.
    And I already have dual pipes out of the cat, and the headers should match up to my down pipes coming into the cat so I might just leave it how it is. It should all match up right, and the headers are 2,1/2 inch just like my 4.3L ones right?
  8. timhall1787

    timhall1787 New Member

    just change the injector to 350 injectors. should be 61lbs/hr or close to.
  9. outalne94z71

    outalne94z71 Member


    changing injectors does nothing productive for swapping from a v6 to v8, and the tbi bores are bigger on the 5.7 vs the v6 as well so just slapping injectors in a v6 tbi is the wrong thing to do as well.
  10. timhall1787

    timhall1787 New Member

    your right. i was thinking it said 5.0 to 5.7. i am doing a 305 to 350 so i was looking for some extra info and misread.

Share This Page

Newest Gallery Photos