Originally Posted by jimlab

I ran 10-gauge power and ground for each pump directly from my battery, which is behind the driver's seat. I used separate wiring and two Bosch 30-amp relays so that I can trigger the second pump based on rpm (with an MSD rpm switch) if I want to, or just turn them on at the same time and run both pumps full time.

Here are some rough sizing guidelines...

Up to 250HP - 5/16" or -04 AN
Up to 375HP - 3/8" or -06 AN
Up to 550HP - 1/2" or -08 AN
Up to 800HP - 5/8" or -10 AN
Up to 1200HP - 3/4" or -12 AN

To determine return line sizing based on fuel pump output...

Up to 45GPH - 5/16" or -04 AN
Up to 90GPH - 3/8" or -06 AN
Up to 180GPH - 1/2" or -08 AN
Up to 360GPH - 5/8" or -10 AN
Up to 720GPH - 3/4"or -12 AN

Sounds like a plan. The Bosch pumps are big...