How do I vent a fuel tank in the rear, on a 1974 cuda?

[Aracer]

Has anybody figured out a way to vent the gas tank up high on the sheet metal, in axle area?
     The reason is to use the factory 5/16" vent line, for a fuel return. 

[soundcontrol]

 
I'm also curious how the vent should be on a tank with a return line.

[jhaag]

Use a vented cap 

[burdar]

I believe 74 is the same as 73.  73 uses a 5/16" supply line and a 1/4" vapor line.  Is 1/4" large enough for a return?  If it is, then plug the four vent nipples on the tank, use a sending unit that has a return nipple already on it and use a vented gas cap.

You probably could have an extra nipple added to the sending unit if yours doesn't already have one to save some money.

[Aracer]

The same,, the 4 tank vent lines go to a container on the cross member,,with a hose to the 1/4" vent tube,, it goes to the engine charcoal can and then to the carb. Mine is a passive open hose up to and under the air cleaner.
      I will put a brass nipple with a .060 restriction into the unused plug on the pressure regulator. .060 is just enough to keep the fuel fresh and not over work the regulator and fuel pump. It will feed into the 1/4" vapor tube. This 1974 version has the check valve back at the fuel vapor tank collector.
     Back at the tank,, I have a return nip. on the fuel gauge bung to hook up to the 1/4" tube.
      What I think, is that hose to the tank vapor separator should be run up high and across the shock member, and fitted with a tiny filter for vapor relief or air intake when the fuel is used. My concern is rain water mist getting in the tank.
     Is this idea any worse than my 1968 that has the vent tube in the rear frame? It vents from the top of the gas fill down inside the trunk and out to the frame. I put a tiny filter in the trunk high on the fill tube in place of a rubber fuel line that connects the 1/8" tubes as a splice. And I always use vented cap.

I could just add a new 3/8" fuel line and keep the vapor like it is. And use the old 5/16" fuel line for a return. Which is too much work, to bend and clamp down for now.
       

[burdar]

If you are running a vented gas cap, then you don't need the vapor separator even hooked up. It's not doing anything unless your using a sealed gas cap. You can plug the four vent nipples...or plug three and use the fourth for the return.

[Aracer]

If you are running a vented gas cap, then you don't need the vapor separator even hooked up. It's not doing anything unless your using a sealed gas cap. You can plug the four vent nipples...or plug three and use the fourth for the return.

I figured it (v.s) burped the tank no mater what grade it's parked on. Back when new, it would fill the carbon can up front and spill gas on the ground if parked facing down hill with a full tank on a hot day. So if it were parked facing up hill the expanding fuel might force gas out the vented fill cap, if the separator is plugged.
     Since it doesn't mater; I'll just put a tiny gas filter on the tank separator, as out lined before. Reroute the 1/4" to the return nip on the tank gauge.   And be happy

[HP2]

Use a vented cap 

How can you tell vented from non vented caps?

[70chall440]

How can you tell vented from non vented caps?

Usually says it right on the cap.

[dfrazz]

How can you tell vented from non vented caps?

blow into cap and you can hear the air go through.  you can also just drill a small hole if you are not sure.

[Katfish]

Exactly what I did, blow test, then drilled small hole in my aftermarket locking gas cap.

[YellowThumper]

I removed the canister on my 74
Room for turbos and adding FI. The 1/4 diameter line is not 1 piece. There is a rubber section located about same area as passenger seat. Removed the front section and added a new one that goes up into the outer fenderwell. Bent a 180 on the top so opening points down and added a fuel filter to it. That keeps out any debris. Also end is located up high.