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Fuel Tank Swap Questions

Discussion in 'The Garage' started by Rolled, Sep 23, 2004.

  1. Rolled

    Rolled 1/2 ton status

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    I know I have read info about this in the past but I was unable to find the threads, via search, so I'll as ask... If anybody has a link that answers all my question, I will be most appreciative /forums/images/graemlins/smile.gif


    Here is what I am going to do:

    1987 K5, 305 FI

    My 25 gallon tank has been puncured so I am going to replace it. I want to put in a 31 gallon tank in its place.


    1. Do I need to get a 31 gallon tank from a FI rig (87 to 91) or is the carb version tank the same?

    2. Is a Suburban tank the same as the Blazer/Jimmy?

    3. Straps are different, I suspect. Am I correct in this assumetion?

    4. Is the sending unit different on 31 gallon compared to the 25?

    5. Is the top side of the tank the same, like the filler neck, overflow? Or do I need to get parts for those as well?


    The swap seems pretty straight forward but if you have any advice, or can think of something I did not ask, please let me know.
     
  2. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    we did this a few weeks ago.

    the straps are differnet
    the sending unit is different
    the FI tanks are different than a carb tank.
    the rest of the tank is the same, as in the filler neck, vent etc.
    i don;t know if the skid plate is the same or not, our blazer didn't have one on it and we didn't put on back on, its a road only truck anyway.

    not sure on the surburban tanks
     
  3. 84_Chevy_K10

    84_Chevy_K10 Banned

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    EFI tank has baffles inside it.
     
  4. Rolled

    Rolled 1/2 ton status

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    Thanks fellas. I am packing for my early morning trip to my favorite truck junk yard /forums/images/graemlins/smile.gif
     
  5. hawkeye649

    hawkeye649 1/2 ton status

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    Aren't the suburban tanks bigger? Like 40ish gallons?
    The best I've tracked down is an aftermarket 43gal tank for my 1990 Jimmy. I don't mine the large $$ fill ups, I hate the large $$$ fill ups every 3 days... /forums/images/graemlins/thinking.gif
     
  6. Rolled

    Rolled 1/2 ton status

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    [ QUOTE ]
    Aren't the suburban tanks bigger? Like 40ish gallons?
    The best I've tracked down is an aftermarket 43gal tank for my 1990 Jimmy. I don't mine the large $$ fill ups, I hate the large $$$ fill ups every 3 days... /forums/images/graemlins/thinking.gif

    [/ QUOTE ]

    Autozone list the burb as having 3 tank sizes. 25, 31, and 40. I hope the Suburban tank is the same since they are much easier to find than Blazers. I rarely see a TBI Blazer being parted out, private or at the JY, but the FI Suburbans are everywhere...


    Maybe I can squeeze a 40 gal in there /forums/images/graemlins/smile.gif
     
  7. hawkeye649

    hawkeye649 1/2 ton status

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    IIRC the 43 gal kit was $475 plus sender/wires/and I think even pump. I can get you in contact with them if you'd like.
    E-mail me:
    pde_on_ebay/forums/images/graemlins/k5.gifcomcast.net
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Sender for the suburban is listed as a different part number, but I have no clue why...the tank depth IIRC is the same. I'm really curious to see why the 31 gallon suburban tank won't work.

    I wouldn't buy a used baffled tank without pulling the sending unit out and inspecting the baffles. Factory baffles are plastic and appear to be broken about 75% of the time (of course, these trucks are all in the wrecking yard for SOME reason) and probably won't hold up well to serious beatings.

    Fill neck is part of the tank, so not much you can do with it. The change in fill hose diameter was much earlier than FI though, so no worries there.

    Skid plate I've seen on the military Blazers with the small tanks is the same as the one for 31 gallon tanks, so if there is a large gap between your tank and the skid plate (if present) now, then it will likely fit fine.
     
  9. Rolled

    Rolled 1/2 ton status

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    I got a smoking deal from the JY this morning. I found an 87 TBI Blazer (to my surprise) and for $65, I purchased the following.

    31 gallon tank
    Sending unit
    straps
    Skid plate
    and I got the hoses so I can show the parts counter guys what what I need to replace /forums/images/graemlins/smile.gif

    I got a new fuel pump and strainer from Autozone, as well. All together, the swap is costing me around $100. Not too bad..

    There was a TBI Suburban with the 40 gallon tank but it looked to long (front to back) for the Blazer...

    dyeager535 - Currious, what problem would a cracked baffle cause? I actually don't even know their purpose /forums/images/graemlins/smile.gif
     
  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    The purpose is to keep fuel by the pickup so the pump won't cavitate.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    If the baffle breaks, you might clog the pickup, (hard to do, but possible) you might screw up the sender or the gauge reading, and it might die under certain conditions, like low fuel and a steep angle or bumps.
     

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