carter fuel pump fuel filter flow requirements?

I had an MPI marine engine installed in my boat and i'm working trying to do a process of elimination here. The people I bought the motor said the high pressure pump will squeal if it doesn't get enough fuel flow. I never saw anything in the manual, about flow requirements but I'm wondering if maybe I need a higher flow racor on the boat. Mine is a 60gph rating, but looking up the specs for what looks like to be a carter low pressure fuel pump it flows anywhere from 50-72gph free flow rating. I wonder if this is my restriction squealing issue? I don't think it's the belts because i've tightened them and haven't noticed a difference. So since this engine has a return line it makes me wonder how much fuel it's actually flowing through my racor main filter.

I would think that a Parker/RACOR rated at 60 gph would be sufficient.

Today I tested the flow and pressure of two fuel pumps (LP/HP) on my VP 5.0Gi engine.
The low pressure pump (3858260) pumped about 70-75 gph free-flow and about 8psi.
High pressure (3857650) pumped about 40 gph at about 50 psi.

I was supprised to find that flow rate for the HP pump was about half that of the LP pump.
This situation seems reasonable because of the tighter seals required for higher pressure.
Anyone know if these results are normal and within specs?