What fuel system to use

Run twin walbro 255 fuel pumps on anything above 600HP. Run them with an aeromotive boost referenced regulator. One fuel pump can be operated via Hobbs switch for 'x' amount of boost pressure to operate. 8-10AN forward, 10AN return line. You will have nothing but issues if you run anything less with multi pump, high pressure applications. You can't think of this in N/A sense anymore, with 6.5-7.5psi of pressure at the carb and where 3/8 line can support 500HP you will need at minimum 1/2"-5/8" forward and 5/8"-3/4" return. You can't leave it to chance with boost, starving your engine at full boost (leaning it out, detonation) and cracked pistons or rings because you cheaped out on some fuel line. Don't skimp on this, even if money is tight. Use quality fuel line, such as Russel or Aeroquip. You would want the pump lower than the tank to push fuel rather than pull. A good regulator will hold 40+psi (maintaining your 6-7psi base fuel pressure) while increasing pressure 1:1 with boost. Their is no reason to cobble something together with boost, as you have very little room for error. You will also need a good wideband for tuning, AEM Eugo is a nice one, also LM-1/2 from innovate.