Carburetor Vacuum Lines

[dzwestwindsor]

Hi guys,

I have a 1971 C20 with a 350 and Quadrajet carb.

Take a look at pictures of my carb:
front view: http://imageshack.us/f/407/cdiv.jpg/
diagonal side view: http://imageshack.us/f/545/3d7u.jpg/

I have two concerns:

1. In the front of the carb, what is that vacuum port for? What is it supposed to be connected to? If I put my finger on it, I feel a pretty good suction. I feel like it's missing a hose to somewhere.

2. In that diagonal side view image, is that hose supposed to be routed back up to the air cleaner? When I got the truck it was only connected on the carb end so I guessed that the other end goes up to the cleaner, but I'm not sure. Is it the hose that keeps the float bowl fuel pressure constant?

It'll be great if someone could point out what those two vacuum ports are for.

Thanks in advance,
David