Carb & Idle Help

[RDrancher]

I've dealt only with diesels for the last 15 years, so I could use some help with this. I recently purchased this low mileage '85 Suburban. The previous owner replaced the HEI cap, plugs, wires and a rebuilt Quadrajet. I believe the carb is a smog model since the idle mixture adjustments are epoxied.

The engine runs nice but has a rough idle and smells pretty rich. After replacing all of the vacuum lines and plugging the ones on the carb that looked to be heading to emission stuff, I bumped the timing up by ear (no timing tab on the engine). It runs better, but didn't change the rough/rich idle.

I could use help in resolving the rough/rich idle, but first...where does the hookup my finger is pointing to in the photo tie in? I think it's for the secondaries, but could it have anything to do with idle and fuel mileage? The smaller hookup under that's same pot is tied into the vacuum system. [IMG][/IMG]

I plan on swapping the carb/manifold out for an Edelbrock setup, but for the time being, if I can get it running right I could use those funds for drop spindles and springs.

Sorry for the huge pic, I'm still figuring this site out. Thanks.