Gas Tank Plumbing

[Bluegoose972]

I've installed a new gas tank for my blazer, replacing the old rusted and dented unit with a poly unit. So far, so good. Now I need to hook up the hoses....Not so good. Here is what I see:

On the passenger side, I have one 3/8" fitting, which I believe to be a vent. I connected this to the hard plumbing vent line on that side...no problem there.

On the driver side, in addition to the gas filler neck, I have two additional fittings....one 3/8" and one 5/16". I believe the 5/16" is for another vent hard line, which is located nearby. But what is the second 3/8" vent line for?

Does anyone have a picture that illustrates the correct plumbing for this unit? I been checking my misc manuals, but have yet to find anything that identifies what these three vent lines are for.

Thanks,
Rick