Fuel restriction w/ 6an line?

I am using -8 an from the tank to filter then to pump then to regulator. After regulater it is 2 -6an lines to 750 holley double pumper. This is on a 388ci sbc in my race car running e-85. I haven't run the car yet but from my own previous experience it should work well enough for 475-500 horses. I think a dual feed carb with two -6an lines would be better for your set up or a -8an line to carb if you must run a street carb like that.
RTR