What makes you think it is over driven? There is only one size pulley for all motors (6, SBC or BBC all share the same size diameter pulley with different pulley groove centerlines) as the pump does nothing with the wheels centered, and only moves an increasing volume of fluid as the wheel angle increases at the valve in the steering gear box.
If you run the fluid level low it will aerates the fluid and burn up the pump. If you have a SBC water pump pulley on your BBC, or a SBC pump pulley on your power steering pump then the belt mis-alignment will cause the seals to blow burning up the pump.
Mis-matched pulleys is a very, very common problem on a BBC engine as they were traded around like base base ball cards back in the late sixties (especially the unloved little 396 replacing 307 or 283 small blocks) and as such when they were installed in cars the pulleys never were replaced with a matching set of big block pulleys because the small block pulleys are close enough for most people (who didn't realize the head ache they were creating just because a SBC pulley will bolt up to the BBC mounting holes). The only SBC pulley that will not bolt up to a BBC is the crank pulley because of the bigger bolt and washer used with the big block (I have seen them drilled out to make them almost fit but wobbling wildly). However with the SBC pulley on a BBC the belts will not line up (which is very evident if there is another accessory like an A/C that sits close to it).