I found the online fuel calculators such as Raceworks and Injector Dyamics, along with the walbro fuel pump flow charts with pressure drop, very helpful to calculate maximum possible fuel pump flow (at applied pressure).
Claimed pump rating at 500hp rating is basically zero fuel pressure, 8an line matching outlet minimal length, no fuel filter, and no boost pressure... that’s not real world 3sgte....
Use the calculators for you own application :)