1972 EEC In-Cab Gas Tank Dilemma

[myoldchevytruck]

Below is a diagram of a 1972 EEC Gas Tank. Since the 72 tank is different than the 67-71 (NON EEC), I'm confused about the tank venting. Here's what I know.

There's a vent fitting on the passenger side of the tank

I have a stock charcoal canister and it has an in/out fitting

I have the vent loop tube that goes up to the Passenger Side Pillar (from another truck)

There's a Sending Unit with 2 lines and there's also one available with 1 line


Does anyone know the correct setup. Do I use the Sending Unit with 1 or 2 lines? What is the proper venting for my setup? Do any of these lines go to a vacuum for venting?


BTW, I have a 69' SBC 350/Automatic. Yes, I have a 72 In-Cab Tank. I did not relize it when I got it but thats okay. I have had it boiled clean and sealed.



Thanks in advance.

[myoldchevytruck]

ttt, diagram posted

[myoldchevytruck]

C'mon guys, no-one has a stock 72' in-cab tank setup? Getting close to finally running the truck.

[FormerMember]

You have the proper schematic for the tank there.

If you want to run the later style configuration, that's correct. The earlier style wouldn't have the charcoal canister (AFAIK).

I guess most guys are trying to figure out what the question is?

[Stock72c10]

I have issues with gas smell so I checked out my carbon canister last night (72 C10 straight six). I found that the carbon canister had three lines going to/from it, one went to the carb, one just hangs down towards the ground and is open, the other has been chopped and a screw plugging it (I take it this is the one that goes to the tank). I will be looking further into the correct hookup this weekend to see if I can figure it out. I did notice that in your pic you don't show a hose going to the carb.

[myoldchevytruck]

Originally Posted by grendel

You have the proper schematic for the tank there.

If you want to run the later style configuration, that's correct. The earlier style wouldn't have the charcoal canister (AFAIK).

I guess most guys are trying to figure out what the question is?

grendel, Thanks for the input. I guess my question is, if I use the 72' sending unit - it has 2 lines (one going to the fuel pump and the other going where?) If I use the 67-71 sending unit, my diagram would seem correct for venting purposes. The only other thing for me to do would be to go from the canister to a vacuum (carb or intake) for proper venting.

Originally Posted by Stock72c10

I have issues with gas smell so I checked out my carbon canister last night (72 C10 straight six). I found that the carbon canister had three lines going to/from it, one went to the carb, one just hangs down towards the ground and is open, the other has been chopped and a screw plugging it (I take it this is the one that goes to the tank). I will be looking further into the correct hookup this weekend to see if I can figure it out. I did notice that in your pic you don't show a hose going to the carb.

stock72c10, Thanks for your input also. As far a gas smell, that's what I am trying to eliminate. With the proper venting configuration AND the correct cap (p.s. check your cap because a bad cap is notorious for causing gas smelling in the cab). From what I understand, no line should go to the ground for venting. As far as a line going to the carb or even to the intake, that's what I am trying to figure out. Going to the carb or intake would be connected to a vacuum, ultimately, properly venting the tank. My canister only has 2 lines. Why yours has 3 may be due to different state laws for emissions purposes.