IMO this changes everything.

I would run an intank walbro style 340LPH pump and a regulator that will work at both carb and EFI pressures. A 340LPH pump will easily support 600 HP at EFI pressure, and will support 800+HP at carb pressure. The Aeromotive Phatom line is designed to go into a stock style tank, but a number of other companies have similar solutions. When you go to EFI, you will have to swap a spring in the regulator and hit the road...In tank pumps are quiet and stay cool. Do it once now and be set.

I always run a bypass return.