I will be running the Mechanical Carter Competiton series 172GPH on mine. It has 10 an inlet and 8an outlet......maybe squeeze some juice with it also.
stock for now, works on 440's w/ same psi so....you know what I mean?
Maybe if you plan on reving 8000+ rpm at the track and have big lines or the rest, then the high psi pump is recommended, but 400 ci can live without it.jmo
If you changed the fuel line diameter, then you should increase the fuel psi.