I would think the second line goes to the combination (gas-vacuum) pump.
The full description of that PN (374965-S) can usually be found under BASIC PN 9424 (Intake Manifold) in the MPC and a further detailed description in the STANDARD PARTS CATALOG.
I am sure everyone here will be willing to help you with anything and remember, pictures of the car are welcome...
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- WHY IS IT ... 
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... that everything you buy in the grocery store is either wrapped in or contained in plastic but the government doesn't want you to carry it out in a plastic bag?
WONDERING IN W(BY GOD)V ...
DIAGNOSED CDO - (OCD In Correct Alphabetical Order)