I am building a new 540 motor and I am wondering what fuel system upgrades I will need. The engine started out as a 502 mag 415 HP with electric fuel pump only and the cool fuel system. I am switching to a late model 500 EFI fuel injection system with a Arizona speed mono blade throttle body and 50 or 55lb injectors. What else needs to be done to upgrade the fuel system?? The 540 has Dart pro 1 heads,741 cam, and EMI thunder exhaust producing 650HP. Any input is appreciated. Thanks, Jeff Wurl

Trash the cool fuel. Put an A1000 pump or similar with a regulator. Put a 1/2" pickup and lines and return it to your tank.

Use 1/2 lines from tank all the way thru to the fuel rail. And also make a return line back to tank for unused fuel.

Would you run a water filter or not?? What kind of fuel pressure would you run? Thanks, Jeff

Run a large Wix or Fram water/fuel sep. you'll be fine

Are you reffering to adding a larger Wix filter to the original Merc water seperator. Will the original filter head flow enough? Thanks again, Jeff

No, you need a larger filter head.
Fuel pressure will depend on the tune. You ecm will be tuned for a particular pressure. Should be around 40 psi.
Eddie

I took a 500EFI with close to the same setup. We put in a Scat crank & Rods, 4.25, Bored the block to 4.50", JE 10cc small dome pistons, 741 cam, Dart Iron Eagle heads ported, Arizona mono blade, 9.7CR. I sent it off to Precision to tune & dyno test. The motor made 700 lbs of torque ay about 4200rpm & 631 HP at about 5200 rpm. The hp rolled off quickly after that. The intake will be an issue if you plan on spinning it much over 5000. The dyno showed vacumn increasing in that range which meant it was running out of air. The motor works great, with a different manifold you may get 650-675 HP. The fuel system is all stock 500 EFI with the exception of installing 50lb injectors. Not any fuel isses so you will not need to do any of that. The motors are in t500hps boat. He can provide dyno sheets if you are interested

Good Luck

Linster..Is that 500 EFI running both a mechanical and electric fuel pump or just the electric. Thanks, Jeff Wurl

yes they are running both pumps