Hey Doug -- Topeka is only 1000' above sea level; according to my Pierce Manifolds Tuning Manual you shouldn't need to change jetting until you get to around 4000' above sea level.
When did you last change your fuel filter? If its been a while, I would consider that.
Do you have a gauge on your fuel line? What does it read? My Webers need only about 2lbs of pressure to run well and I'm told above 3lb and the float bowls will get too full.
If fuel pump and filter don't help, you may have a problem with the float level in one or more of your carbs. If your floats aren't set correctly, or if they are filled with fuel (which was a problem with the brass floats Weber used 25 years ago), this can allow the bowls to get too full.
In either case, too much fuel in the bowls displaces the air at the top of the fuel bowl which (if I understand this correctly) is used by the carb to push fuel into the air/fuel mix used to run the car.