What are the symptoms of a bad torque converter?

My cam sheet suggests a 2000 rpm stall speed. And I don't really do too much highway driving so I would be fine with running 3.91 gears. So the converter is not the best but the main hindrance to my performance is the gears I would assume? But I may as well change out the converter as well.

I was planning on changing out the gears pretty soon anyway, I am just running it like this while I finish putting it together.