Can I replace my TBI block and heads with engine from a carburated truck?

Discussion in 'GM Powertrain' started by Big6ft6, Aug 8, 2007.

  1. Big6ft6

    Big6ft6 Rockstar 100 Posts

    I have an 89 suburban with TBI that needs a new engine. I also have an engine from a carburated 86 surburban. Can I simply swap the intake and use the 86 block/head with the TBI setup?

    thanks!
     
  2. Crawdaddy

    Crawdaddy ↑↑↑ Has no life Staff Member 5+ Years 1000 Posts Platinum Contributor

    you should be able to. You may need to swap the heads also, but they should work. You may/will have to swap out some other components that have sensors on them and such to make the computer happy. All this is guesses, but I'm thinking it's possible. going from TBI to carbuerated is much easier :)
     
  3. Big6ft6

    Big6ft6 Rockstar 100 Posts

    I was thinking about that...going the other way to a carb...what all would I need to do about the high pressure fuel pump? Isn't that pump in the tank? I dont' want to have to take the tank down and pull the pump. Or are there aftermarket regulators with return lines etc?
     
  4. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    You can use the carburated short block with your TBI heads and manifold. All the sensors needed to operate the TBI are located in the manifold and heads.
     
  5. collinsperformance

    collinsperformance Epic Member 5+ Years 500 Posts

    you can install a fuel pressure regulator and drop the pressure. i thought the carb motor has the fuel pump on the block --if so you will need a block off plate- these are cheap and easy to find....mike
     
  6. GaryL

    GaryL Epic Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    This is on my theory alone, but you should be able to pull the fuse for the fuel pump, install a mechanical fuel pump and fuel pump rod in the block and that fuel pump should be able to pull the fuel through the electric pump. I added an electric pump to one of my old Firebirds and only used the electric for racing and never had an issue, but never tried it on a factory setup.
     
  7. Crawdaddy

    Crawdaddy ↑↑↑ Has no life Staff Member 5+ Years 1000 Posts Platinum Contributor

    I'm not familiar with carbs, but would there be an issue with using a high-pressure fuel pump with a carb? I would think that the more pressure the better, especially for the high CFM carbs that are dual feed, etc.
     
  8. GaryL

    GaryL Epic Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    On most carbs, the needle and seat will only stay closed up to about 7 psi, after that it will open and overfill the bowls.
     
  9. Toymyster

    Toymyster Rockstar 100 Posts

    No, the fuel injection pump will not work with a carburetor. I highly recommend you stick with fuel injection, but that's just me!! Your 86 block will work in your 89. I believe the heads are the same also, but I think the cams are different! And since you will have everything out, why not do a valve job on your TBI heads and use those?!?!
    If you are going back to a carb, you must drop the tank, replace your fuel pump with a tube, and install an external electric pump designed for carburetors. You can adapt your existing fuel pump wiring to run the new pump!!
    Hope this helps
     
  10. kickercompkid_99

    kickercompkid_99 New Member

    I had a 89 TBI truck that I converted to carburetor, bought the good ole edelbrock intake for the TBI heads, cut all kinds of wires pulled all the BS computer stuff out and for the fuel all I did was get a cheap pressure regulator and put a T in the line before the regulator and used that same fuel pump for the TBI, the T served as a feed line and also as a junction for the return, never had any problems with it at all running it that way, as a matter of fact I still talk to the guy that I sold it too and he hasn't had to touch a thing, don't know if that is an option for you, but it sure worked for me! I did have to get into the dash and pull the check engine light because it was annoying but other than that no problems.
     

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