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Larger fuel tank question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by OneInTheSun, Dec 12, 2000.

  1. OneInTheSun

    OneInTheSun 1/2 ton status

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    I did a search on this but couldn't find a definitive answer - On my 85 K5, is going from the stock 20-something gal. tank to a 31 gal. tank a direct swap? There's a leak back there somewhere and I might end up replacing more than I think, but right now I'm just planning on a new tank and straps. Thanks in advance.

    <font color=blue>Rob
    85 K5</font color=blue>
    [​IMG] 24 beers in a case, 24 hours in a day - Coincidence?
     
  2. nyyef

    nyyef 1/2 ton status

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    i think it is a direct swap. even with the plate. i have noticed on the k5s with the smaller tanks they just have a larger gap between it and the plate.

    Knife.
    knife.coloradok5.com
     
  3. HarryH3

    HarryH3 1 ton status Author

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    If you really want to get serious, take a look at some of the aftermarket tanks. I replaced the factory tank in a '72 Blazer (the original met a horrible death against a rock) with one from Arrow Tanks in California. Had a 45 gallon capacity with the new tank. Filling it was a killer on the wallet, but it would run for a LONG time between fills!

    Haven't ever heard of a K5 with only a 20 gallon tank, but I used to have a '79 Dodge van that was 4WD. It had a stock 20 gallon tank, but there was an optional 36 gallon tank available from the factory. I bought one (with the sending unit and straps) from a junkyard for $40. There were two "spacers" spot welded to the bottom of the body that once removed, made for a perfect fit for the bigger tank. I'll bet it's similar with a K5. GM likes to make everything as interchangeable as possible. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     
  4. shaggyk5

    shaggyk5 1/2 ton status

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    Does anyone possibly know of a place to get a plastic tank? like the heavy duty Polyethtelyne tanks they sell in JC whitney? In Whitney they only sell these for pickup trucks and 71-72 blazers. I am looking for a 31 gallon tank to replace my rusted and leaking OEM on my 85. Anyone?

    shaggyk5

    aint nuthin in the world like a heavy chevy!!
     
  5. Zepplin

    Zepplin 1/2 ton status

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    You could also get a 41 or so gallon tank from JCWhitney. I think it was around $300 though.

    Communication Breakdown
    74 Blazer
    Zeppelin
     
  6. JimmyDie6.2

    JimmyDie6.2 1/2 ton status

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    while were on the tank subject, can I put a 40 gallon suburban tank in my 83 K5?..................js
     
  7. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    the 31 will fit right in with new straps and a new sending unit.
    jimmydie6.2 no a 40 gall sub tank wont just bolt right in i looked into this reacently since i just changed my tank[​IMG] you could make it fit but it would take some mods

    s.smith 77blazer lookin 4 mud
     
  8. shaggyk5

    shaggyk5 1/2 ton status

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    where is a plastic tank (oem) available?

    shaggyk5

    aint nuthin in the world like a heavy chevy!!
     
  9. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Suburban and K5 run the same 20 and 31 gallon tanks. The difference between the two is depth. You will need to find a 31 gallon tank sender/ pickup and straps but it is a direct bolt in. You can not fit a Sub 40 gallon tank. It is longer and you will run into interference with the diff and brake lines. Not aware of a Plastic tank but I personally wouldn't want one. Lot of the Jeepers I run with regret going to the plastic tanks. They have had them crack while getting bounced around, most can't get them to seal at the sender. Even had one guy have dirt get between the tank and the mounts and wore through the tank. Your concern about rusting tank...how old is the one you got now and are you going to keep the truck long enough to have to replace it again? My guess is you got a late 70's or early 80's. Are you really going to have that truck for another 20 years? If the tank is rusted My bet is the new tank will out last the body because the body has to be rusting also.

    Diging it in the dirt with my K5's
    Grim-Reaper
    http://grimsk5s.coloradok5.com/
     
  10. HarryH3

    HarryH3 1 ton status Author

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    The skid plate from a 31-gal Gen 2 Suburban will also fit a similar K5. I've got one from a 70-something Sub on my '75 K5. It's massive! Be sure to remove it your self and take every little bracket and bolt with you. You'll need 'em to install it on your K5.

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     
  11. shaggyk5

    shaggyk5 1/2 ton status

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    good point, i can see what you mean about the truck out lasting a new tank.

    shaggyk5

    aint nuthin in the world like a heavy chevy!!
     
  12. JimmyDie6.2

    JimmyDie6.2 1/2 ton status

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    hey guys thanks for the answers to the 40 gallon question........js
     
  13. Hobbes68

    Hobbes68 Registered Member

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    A 20 gal tank? You must be at the gas station almost every day!!! My 90 Jimmy has a 31 gal tank stock. I'd look in a junk yard for a used tank. SHould only cost $40 or $50 and they will usually guarantee that it's in functional and in working condition. That way you'll get the sending unit with it. Send it out to your local radiator shop to have it boiled out and checked for leaks before you install it.
     
  14. TheBlazerKid

    TheBlazerKid 1/2 ton status

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    i have a 35 gallon tank under my 71...not sure where it came from or anything like that cause my dad put it on along time ago but its great i knwo that much.....but with a bigblock I need it anywho!!

    Theres No Replacement for Cubic Inches!
     
  15. Beast

    Beast Registered Member

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    I have been wondering about the 42 Gal tanks JC Whitney has for 73+ Blazers myself, I have a factory receiver unit that extends the length of the tank and attaches to the frame at four points. Where would the 42 gal tank extend into, are there spacer blocks above even my stock 31 gal tank?
     
  16. HarryH3

    HarryH3 1 ton status Author

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    Beast, the 42 gallon tank is deeper than the stock tank. I doubt that it would clear a receiver hitch. Does JC Whitney list a tech line for that product? You could call and ask them to find out for sure.

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     
  17. Steve_87K5

    Steve_87K5 1/2 ton status

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    I put the NW Metal Products 43 gallon tank in last year. It is a good tank. I have the 31 gallon tank and skid plate left over if anyone needs one.

    SteveB
     

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