Thing of that is 72's at say 70% are only flowing 50.8# of fuel. 50*6 = 300# of fuel. If it flows 350# at 70psi then you're OK. I was told delivery on that pump falls off sharp over 55-60psi. And if your base is 50psi, and you're running 25psi, you're at 75# fp. But if you up your fuel requirement much, I think you'll start seeing those corrections go the other way. LIke Todd said, a 340m would do that just fine for $130, and will support mid 600's HP. (Yes, I know PTE said 750, but I like a fudge factor).
Hate to say it, but I dont think that red pump is in my future. I may never go fast enuf to need it, but I dont wanna haveta worry about it. I think the 11104 (rated to 900hp forced induction) for $400 is a $200 insurance policy. Or even the 11102 for $300 more (rated to 1200hp forced induction)