Snorider:
Currently, it will do 62mph @ 5400 - 5500rpmWelcome to the boards!
First thing I would check is either your pump, or your RPM gauge. If you have an A impeller, I would say your in need of a pump rebuild because that RPM is really high. And did you GPS the boat, or do you have an MPH gauge too? I only ask because that MPH might not be right if you didn't use a GPS.
I would have your pump checked out before you decide on replacing it. A basic rebuild may be all you need.
HBjet