Alright guys, I need some help here. 

454BBC (passenger/2 bolt/ ~325HP). 
Berkeley JC pump. 

WOT - 4900 RPM & 46 MPH - Sea level with 4 adults
WOT - 5100 RPM & 50.6MPH - 3700' elevation - 1 adult.

Pulling a skier, the pump cavitates and doesn't produce much torque. 

Based on the above the assumption has been that the impeller was a C cut, which was causing the high RPMs and cavitation from a stop under load.  I was getting ready to send the pump out to get rebuilt with a new impeller so I pulled it apart and this is what I found inside.  A2 cut impeller, what looks to me like clean leading edges, no obvious issues.  So what gives?  Why are my RPMs so high and having trouble with the holeshot?   

Now I have no clue what to do with the pump rebuild.  I'm glad I might save some money on not needing a new impeller, but at a loss for performance issues.