New Crate Vortec L31 into 94' Sierra 4X4. Any tips for the newbie???

Discussion in 'Engine Performance + Maintenance' started by Old Gasser, Jan 11, 2019 at 11:40 PM.

  1. Old Gasser

    Old Gasser Newbie

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    Hi everyone. I know this has been done thousands of times, but I would like some input before I forge ahead and have to start reinventing the wheel!
    My 94' Sierra has @ 207K miles on it and is tired. It runs fine, but is weak. And the trans is definitely going south! But I will fix that later.

    My question is: What is required to run my stock(or probably upgraded some) TBI, and all my stock accessories,i.e. air conditioning, power steering...etc. on a Vortec 350? I have read some info, but I would really hope some of you guys that have done this could give an idea what I would need to do to make the swap.

    Before suggestions of 383's and LS swaps start rolling in, I'll just say I can get a deal on a Chevy replacement engine in a crate, and even the budget 383 motors I have put together, after machine work and parts will surpass the cost of the crate motor. It's purely a matter of economics. I have two hot rods already, don't need a pickup that will be a pain in the ass too! lol I do all my work myself.

    I bought a beautiful 1994 Z-71 in 1996, only had 20K miles on it. Traded it in on a new 1998 K2500HD with a 454, and drove it until we bought a new 2015 Z-71! I had to do a cam swap on that 7.4, if anybody has a cam go bad I could tell you about that experience.

    I know most of you guys on this board know these trucks very well. I hope somebody can give me a laundry list of stuff I i will need to do , and watch for.

    Thanks in advance, I'm looking forward to hearing from you!
     
  2. letitsnow

    letitsnow I'm Awesome

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    What do you plan to use as an intake manifold? Do you have to worry about the distributor working correctly on the vortec motor??

    I haven't done the swap that you are talking about, but did just install a new gm 5.7 in my '99.
     
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  3. Gramps

    Gramps OBS Enthusiast

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    All your accessories and brackets will bolt up fine.
    You will need a new intake manifold and a tbi to 4bbl adaptor OR a manifold with the tbi boss on it(fairly expensive)

    The distributor will work but you need a melonized drive gear on it otherwise it will eat the cam.

    If you stay with the stock cam then the stock tbi will handle the fueling requirements maybe with a slight bump in fuel pressure.
     
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  4. 86454k30

    86454k30 I'm Awesome

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  5. Old Gasser

    Old Gasser Newbie

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    Thank you Gramps. I do plan to experiment a bit with the TBI, after its running and broken in. I have read some on what that requires. I may put a new Vortec fuel pump in while I'm doing the rest, then tweaking on the TBI as I go. Bottom end torque and economy are my goals. From my observations so far, if I have good torque from @ 1500 or 1800rpm thru 4000, I'll feel this was a success. So far I've just driven highway/freeway, and cruise rpm is around 1800. But pulling my 4 wheeler and all my gear to hunting camp this year seemed to be a chore for the poor thing.

    I'm familiar with the dist gear/steel roller cam situation. I would change the gear.
    Thanks for the input!
     
  6. Old Gasser

    Old Gasser Newbie

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    I know that intake price is scary, huh? Wholly sh..! But, if it solves problems easily and makes everything else work, to me, its well spent. But...DAAAAMN!

    Thanks!
     

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