EFI requires a different fuel system than that used in a carb application, because of the much higher fuel pressure. Typically, injectors are rated for flow at 45 psi. That is the normal pressure setting used with a FAST system, and it is best set using a bypass regulator. A pump that can provide sufficient pressure is a must, and it also must flow the required volume for the power output of the engine. FAST's tech help can provide sizing information on both the fuel system components, and the injectors themselves. Size and capacity has to match the application.