Before tearing into that carb, you might want to verify exactly what is causing the fast idle.
How many RPMs is it fast idling at? Does the fast idle RPM change?
Does it fast idle at cold start?
That carb is a fairly complex design so there could be a number of issues causing a fast idle.
As you know, there are other things that can cause a fast idle.
Are you completely satisfied there are no vacuum leaks Ė tubing, carb gasket, intake manifold gasket, loose nuts and bolts?
Have you checked the ignition timing and the entire throttle linkage?
Has the engine been recently tuned?
Are you driving the vehicle in a big change in elevation?
Have you recently added any kind of fuel additive or carb cleaner?
Please let us know what you discover.