The first issue was the paddle style impeller; it had to be replaced with a much more efficient scroll type impeller.
I had been running an OEM modified water pump with a scroll brass impeller for a few years & the flow/ cooling was much improved over OEM. With that study concluded, we opted for an ultra lightweight anodized machined impeller for the Forza pump design. Note the difference in picture to your left. OEM impeller is on the left Forza version on the right.
Internal comparison, OEM internals upper left, FORZA version, lower left.
Note how large the shaft diameter is, also note that the components such as the impeller & pump pulley are less that half the rotating weight in our new Forza pump design.
The Forza water pump is designed to last 100,000 miles & does not need to be serviced or replaced at 30,000 mile intervals.
Forza high performance Ferrari 308/328/Mondial water pump