1962 Chevy Impala idle problem

A new 4 barrel carburetor was put on my impala before I bought it, I dont think it was ever tuned. I syphined all the old gas out and put new gas in. The car starts if you choke it and runs pretty strong. As soon as the choke is disengaged the car idle drops a lot and dies. To me it seems like the idle is too high when choked, but the idle skrew is backed out all of the way. Do you have any solution to this problem that im having? Thanks.

dustin