For 250 lph (400 HP), you can pick one up at your local ford dealership for around $120
Focus Fuel Pump: 3S4Z-9H307-BC
Instructions: http://www.dndgarage.net/focuspumpinstall.htm
For 280 lph (500 HP), you can also run an Aviator fuel pump. It flows a little more but costs $275. This...