1986 Chevy Caprice Flooding

This car has only 81,000 original miles. The problem I'm having has been gradually getting worse over the last 3 months. It started when I would try to pass someone on the highway and it would bog out. I installed new plugs, new wires, new cap, and new rotor. The problem persisted. I have since changed the alternator, fuel pump, and installed a new battery. Currently the car will start on the first try and idle for approximately 30 seconds before it floods itself out and dies. I can't get it to rev or do anything except idle and flood. I was told that the float had probably developed a leak and sunk. Upon removing the top of the carb the float appeared to be floating properly so I left it alone and put everything back together. This car has a lot of emissions on it and I'm unsure as to where my problem exists. Any insight would be appreciated. Thanks!