gas tank vent question

[Castle]

hi everyone, I have been working on a 1968 Newport....bought it last July. there are two vent tubes that come out of the gas tank, do they perform the same function, and what is that? Is it bad for engine performance if one of them is plugged up? Why does one of them go through the trunk cargo space?
Thanks for your input!

 

[67Monaco]

Dont plug either, youll create a vacuum in the rank amd fuel will not flow to the carb without removing the gas cap. Eventually, while driving anyway. It will seem lile a vapor lock at worst or it will surge at best.

 

[Castle]

I know my question was ridiculous, but I was confused as to the line that goes up and through the trunk.... thought the lines might be redundant.... I’ll make sure both lines “breath”... thanks for your reply.

 

[67Monaco]

Theres a reason why it runs in to the trunk and backnout. For the life of me i cant remember but i know its been covered here before.

I found out the hard way as mine were plugged while i was welding underneath. I have a thing about gas vapors and sparks. Anywho.. I forgot to unplug them and went for a spin. About 3 minutes later i had an expexted and really bad surge at cruising speed. Investgation later validated the plugged vents. Removed the plugs and the surging stopped.

 

[cbarge]

The vents helps with delivery of fuel to the engine. Also when fueling up prevents any splashback fron the nozzle. Tank needs to breathe to keep it collapsing within itself.
Remember this is old school technology and simple science way before the implimentation of evap and emission systems.