Mechanical Fuel Pump limitations?

I am building my fuel system for my 408. It is a stout build: aluminum CNC220 heads, forged bottom end, @50 .251 in and .259 ex with 608 and 625 lift solid flat cam. Worked Edelbrock Airgap intake and a Thumper Carb.

Question is, how much will a mechanical fuel pump support?

Thank you in advance!