Your torque converter is fine and not costing you power. As soon as you are over roughly the stall speed the converter it is up to the output of the engine to pull the car. If the converter was bad your trans would be shot as it creates a huge amount of debris and will destroy a trans in a hurry. It will also make a lot of noise. Your converter is working fine. A looser converter will NOT give you more HP no matter how you slice it and many times will lower your upper rpm HP because it will be looser across the board. A looser converter is only going to make the car quicker from a stop IF you have good traction-Lower ET, but it wont make a car faster-higher mph on the top end unless the converter to start with was not very efficient. Once you go IC and drop pulley size the car will definately have more power all over and you will feel differently
