77' Stepside - SBC 350 part ID and Vacuum Line Question

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Orion

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CA
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Orion
Truck Year
1977
Truck Model
C10 Stepside
Engine Size
Small Block 350
Hi all. My 77' Cheyenne has been driven 3 or 4 times over the last 15 years, but parked for the last 12. I'm finally getting around to tinkering with it again, though I never learned how to do much beyond basic maintenance. I know almost nothing about smog stuff. Can any of you identify these parts? Right now I've got a small mess of vacuum lines:
- A part I don't know the name of has a short line connected to nothing, not capped off. I think this may go to air cleaner? Also has a port with no hose attached, also not capped.
- 3 hoses from some part I don't know the name of that go to carb, or dead end to nowhere and are capped with a bolt, or feed back into the hose coming from the distributor with a T fitting.
- 1 line from distributor to carb. Normal, right?
- 1 line from valve cover (PCV?) to carb. Also normal, right?

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Thanks in advance for any help sent my way. Much appreciated.
 

fast 99

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Engine Size
350
2 may be a diverter valve for air pump system, 4 is a TVS thermal vacuum switch. With aftermarket parts it may be difficult to make everything operational. Looks like your from California does it need to pass emissions?
 

Orion

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Joined
Jul 27, 2023
Posts
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Location
CA
First Name
Orion
Truck Year
1977
Truck Model
C10 Stepside
Engine Size
Small Block 350
2 may be a diverter valve for air pump system, 4 is a TVS thermal vacuum switch. With aftermarket parts it may be difficult to make everything operational. Looks like your from California does it need to pass emissions?
Fortunately no need to pass emissions in my county. I just figured all this stuff is here and ought to be hooked up correctly if possible. From what I've seen, deleting smog stuff is popular when it's not required. I'll look into that diverter valve you mentioned - not familiar with any air pump systems. And thanks for ID on #4, I'll look more into that too.
 

fast 99

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Engine Size
350
Try to find the emissions label here, vacuum diagrams are on it.
 

Orion

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Location
CA
First Name
Orion
Truck Year
1977
Truck Model
C10 Stepside
Engine Size
Small Block 350
Try to find the emissions label here, vacuum diagrams are on it.
Where is "here?" Nothing under my hood anymore if that's what you meant. I did find a bunch of diagrams from the 77 service manual, just need to narrow down my setup. My truck never had factory cats despite having some other California emissions stuff. Other forums have mentioned Federal or Canada trucks having similar setups (not exact) but without the strict CA requirements. Also emission requirements/parts seemed to change for all around this year of truck, complicating things even more. Like you said, might all be moot with aftermarket carb and intake.
 

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