Someone school me on converter/pump relationship please!

I'm guessing he's saying you will need a completely new impeller side of the torque converter. In a way, the impeller can be thought of as the "pump" of the torque converter.

I talked to a different place and that's exactly what they said. It has to do with changing the stall on my existing converter. So who here runs 3500-4000 stalls on the street?