I couldnt find a vacuum line section so i thought i'd just put it here and the line may very well go to the carb. Anyways, ive looked for it everywhere and i cant find any information on what it is, what it does, or where it goes to. Any help'd be appreciated. I guess im just going to have it blocked off for now.

There are several things that can attach here. Maybe it depends on the year/model/motor. There should be a line that connects to the cabin that goes through the firewall - this usually controls the heater & a/c vent operation in the newer models. There is a line that runs to the cruise control. There is a line that runs to the evap canister. There is also a line that runs to a ball under the driver side front fender (like under the battery tray only on the driver side) - this ball is somewhat of a vacuum reservoir that 'holds' vacuum for the heater & a/c controls to maintain function even when vacuum is low.

There is also vacuum lines to the EGR, the MAP sensor, and maybe other sensors (I'm no expert on TPI systems, only have knowledge with TBI).

Hope any of that helps! That's what I remember - there may be more.

Hey, thanks a lot for the quick response. I hadnt even left the site yet haha but im really sorry, i wrote it up pretty quick and forgot to put the eninge model up. We recently just put in a carbed 72 monte carlo 350 so we've been working on putting it all together with the stock 87 iroc stuff.

The AC's been taken out and we're not planning on putting it back in, at least for a long while, and i've also removed a lot of emmisions and that ball thing so im guessing i should just plug it with something? When its just left open there's an unattractive hissing noise and there is ussually a bit of run-on when i turn the engine off. It also seems to idle better when its plugged. Could be just me but i dont know.

Basically, i was just wondering if it should somehow be attatched to the carb to help out with the idle/etc

http://www.thirdgen.org/techboard/fa...-diagrams.html (Vacuum Diagrams)
http://www.thirdgen.org/techboard/at...se-routing.jpg

Note that fitting isn't on the diagram. That means it isn't part of the emissions equipment, so it won't be for the vapor canister, EGR, MAP sensor, or other sensors.

No - nothing needs to be connected there for the carb. I have my heater & A/C line hooked there, and the vacuum for my TCC lockup, and the 'ball' to hold vacuum for the A/C controls, and I think that's it.

Alright, thanks a lot for all of the info. Im gonna look around at the A/C stuff tomorrow. Car does run noticibley better with them plugged though