Curious what those of you with built 454's are running for fuel systems at around 550-580hp. My engine will be right around 580hp and I have a raw water pump driven fuel pump. Choices are scrap the new merc mechanical for an electric with larger pickup in the tank and new fuel filter head, along with a regulator. Or I can re use the arm from my new pump and bolt a KE high output lower onto it along with above mentioned parts. Thoughts?

At that power level I would stick with the stock mechanical pump. Install a fuel pressure gauge if you don't have one.

I run Mallory electric 140's below my fuel pickups in my bilge. I was running 600HP 6500RPM.

Yeah I plan on running around 5,600-6,000 RPM max. Just have heard that the merc mechanicals can easily support this by some, and that they most certainly cannot by the other 50%. I prefer electric pumps, and especially the Mallory brand, but they seem to be more failure prone vs mechanical pumps.

What has your experience been running them? I would install a pressure gauge and a relay.

I run a relay between the ignition and the fuel pump. I run a pressure regulator right before the carb at 9psi. I am now wiring the ignition through a low pressure sender/switch to shut off power during in case of low fuel pressure. I use to run the sea/fuel pump to to feed Holley 110's on my Merc 420's until the sea pump cam failed and I dropped a valve.

That's a brilliant idea! Please PM me said parts to accomplish this. I personally hate the idea of a sea pump driving my fuel delivery and would like to avoid what happened to you. I just rebuilt my entire sea water pump as it was flooded with fuel. Great design mercruiser.......

rookie i am also interested in how your setup works and what parts you have pm me or post it up here thanks

Sorry, didn't see the replies to this thread.
I just use a normally open Bosch relay. Run you ignition wire through the fuel pressure switch. When pressure is above 4psi it will then send 12v through the fuel pressure switch to your relay. Then the relay will close and send 12v battery+ to your ignition box from the 12v from the relay.
http://www.amazon.com/Edelbrock-7221...+safety+switch
http://www.amazon.com/Pack-Relay-Har...+normally+open