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Going to 20 gal saddle tanks

Discussion in 'Carb Fuel Systems' started by BigDaddy72, Oct 22, 2020.

  1. BigDaddy72

    BigDaddy72 Full Access Member

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    First Name:
    Travis
    Truck Year:
    1974
    Truck Model:
    C30 Chassis Cab
    Engine Size:
    496
    does anyone “clearly” know the part number for the switching valve for dual tanks?

    I’ve see a few variations and want to make sure I order the correct one.

    1974 c30 496
    (if there is a difference between SBC and BBC)

    Thanks!
     
  2. dvdswan

    dvdswan Full Access Member

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    Truck Year:
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    Truck Model:
    K10
    Engine Size:
    350
    I don't know the part number but it is a 3-port switching valve with one connection point.
     
    BigDaddy72 likes this.
  3. dusterdude

    dusterdude Member

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    Ac delco u7000 is the 3 port valve.

    Sent from my LM-X420 using Tapatalk
     
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  4. BigDaddy72

    BigDaddy72 Full Access Member

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    Engine Size:
    496
    Thank you!
     
  5. BigDaddy72

    BigDaddy72 Full Access Member

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    496

    Just checked and that part number is for later model trucks.

    Mine is a 74. That’s why I was asking because searching it gets pretty confusing and I pretty sure the older model valves are different.
    I really appreciate the response regardless.
     
  6. dusterdude

    dusterdude Member

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    I looked it up for a 74,not sure what the deal is.

    Sent from my LM-X420 using Tapatalk
     
  7. 75gmck25

    75gmck25 Full Access Member

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    Truck Year:
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    Truck Model:
    K25 Camper Special TH350 NP203
    Engine Size:
    5.7
    Depending on emissions, you may need a six port or a three port valve, but SBC and big block use the same valve.

    My K25 has a fuel return line so it uses a six port. The old style six port with a single power terminal (like mine) is no longer made, so junkyard is the only source. Newer six port valves have multiple electrical terminals (6?) and there is an article out there about how to adapt a newer valve to an older truck. Try a google search for it.

    https://www.summitracing.com/parts/...oUuM9JzSVie3lpKXv9bu5TMRlBtKCyORoCPZMQAvD_BwE

    I don’t think the link above is exactly the right valve for a single terminal, 3 port application, but it is a close equivalent. I have never found a new six port with single electrical terminal.

    Bruce
     
    Last edited: Oct 23, 2020
  8. Bextreme04

    Bextreme04 Full Access Member

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    Didn't 73-74 have a manual cable actuated valve?
     
  9. BigDaddy72

    BigDaddy72 Full Access Member

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    Engine Size:
    496
     
  10. 75gmck25

    75gmck25 Full Access Member

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    5.7
    I have the ‘74 shop manual, and it shows an electrical connection for the tank switch. I have never seen a cable operated switch on a squarebody.

    Bruce
     

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