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Belt sizes

Discussion in 'Tech Discussion' started by MisterB, Jun 12, 2020.

  1. MisterB

    MisterB Supporting Member Supporting Member

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    First Name:
    AJ
    Truck Year:
    1980
    Truck Model:
    GMC K2500 4X4
    Engine Size:
    350
    I've got a 350 with power steering and no A/C. I would like to replace both the fanbelt/alternator and the fanbelt/power steering. NAPA shows both belts are the same exact part number. Does that sound right?

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  2. Octane

    Octane Full Access Member

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    First Name:
    Eddie
    Truck Year:
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    Truck Model:
    K10
    Engine Size:
    350
    A Gates 7360 power steering to fan. 1977 k10 350 is what is on mine.And a 7448 for fan to alternator.Mine also is a non a/c
     
  3. MisterB

    MisterB Supporting Member Supporting Member

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    Engine Size:
    350
    Interesting. I wonder if it changed in 1980, or if it makes a difference mine is a 3/4 ton K25?

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  4. Octane

    Octane Full Access Member

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    Truck Year:
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    Engine Size:
    350
    I dont know about the other models.I replaced my belts in 2018 because they had been on the truck since 2003 and I was afraid they would rot off going down the road. Lol
     
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  5. Chevyguy

    Chevyguy Full Access Member

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    Truck Year:
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    V20
    Engine Size:
    5.7 Litre
    It depends on how much adjustment room you have. As long as a belt fit's the Pulley's correctly a shorter, or longer belt will fit as long as the proper tension can be put on it. This Summer the serpentine setup I pulled off a 92 GMC Sierra 5.7 is going on my 87 V-20.

    Clayton

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  6. 80BrownK10

    80BrownK10 Full Access Member

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    First Name:
    Nate
    Truck Year:
    1980
    Truck Model:
    K10
    Engine Size:
    350
    I have an 80 k10 with 350. I do not recall two identical belts on it. I do have AC but not running the belt as it doesn't work anyway.

    I do remember getting a wrong belt for the PS I believe first. There several belts that could be on it if I remember right. Tomorrow I will get the numbers off mine if you want
     
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  7. 75gmck25

    75gmck25 Full Access Member

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    Location:
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    First Name:
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    Truck Year:
    1975
    Truck Model:
    K25 Camper Special TH350 NP203
    Engine Size:
    5.7
    For my ‘75 K25 the belts are definitely not identical in length.

    There are two choices for my PS belt. The shorter one only goes around the crankshaft and PS pulleys. The longer one (with HD cooling) also goes around the water pump pulley. With the longer belt you can have a loose or broken alternator belt, and the PS belt will still keep the water pump turning.

    Bruce
     
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  8. MisterB

    MisterB Supporting Member Supporting Member

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    Truck Year:
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    Engine Size:
    350
    Thanks guys. I took a pic of my belts, and one of them still had the NAPA part number on it, which matched the part number their web site still shows is correct. The other belt is more worn, and I can't see a part number on it.

    Went ahead and stopped by NAPA, and they confirmed that both belts should be the same size, so I paid for the online store pickup order. I haven't replaced them yet, but I'll let everyone know how that goes. I'm hoping there is enough adjustment to make the other belt fit, but we shall see. I wouldn't be too surprised if I have to take the old belt in to have them manually find one that is the same size

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    [​IMG]
    [​IMG]
     
  9. Grit dog

    Grit dog Full Access Member

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    Engine Size:
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    Take belt off measure the length, buy the same length or one size longer or shorter if it helps with the adjustment range.
    You can do all this from home and know which one you need to buy before even going to the store.
     
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  10. 80BrownK10

    80BrownK10 Full Access Member

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    Truck Year:
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    Engine Size:
    350
    How many blades is your fan??

     
  11. SquareRoot

    SquareRoot Full Access Member

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    Go to the wrecking yard and pull the entire serpintine system off a Vortec sb. It's the best "less than a $100" upgrade you can do. Dump the ancient Vbelts.
     
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  12. 1987 GMC Jimmy

    1987 GMC Jimmy Automobile Hoarder

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    Engine Size:
    350
    Call me crazy, but I like the v-belts without the smog pump.
     
  13. Chevyguy

    Chevyguy Full Access Member

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    Engine Size:
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    I got mine off a 92 GMC 2wd 1/2 ton. The fan won't fit my 87's shroud so I need to get a 19 inch reverse rotation fan. I'm going to upgrade to a 115 amp alternator. My serp setup cost $125, hope to install this summer.

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  14. Chevyguy

    Chevyguy Full Access Member

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    Engine Size:
    5.7 Litre
    Pull it and plug off the exhaust manifolds.

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  15. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    First Name:
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    Truck Year:
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    Truck Model:
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    Engine Size:
    5.7
    Is your setup a belt that goes around crank, waterpump, and alternator, with another belt that goes around the crank, waterpump, and power steering?
     

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