I NEED TO KNOW WHAT KIND OF FUEL PUMP YOU GUYS ARE RUNNING,I HAVE A 540 WITH THE STOCK FUEL PUMP MOUNTED ON THE SEA PUMP,SEEMS LIKE IT IS RUNNING OUT OF FUEL ON THE TOP, IT GETS TO ABOUT 4700 RPM AND STARTS TO FALL OFF TO ABOUT 4500 THEN BACK UP TO 4700 THEN SOMETIMES IT WILL BACKFIRE THREW THE CARB.I HAVE CHECKED THE FUEL PRESS. IT STARTS AT 7 PSI THEN DROPS TO ABOUT 5 AND STAYS THERE,BUT I AM WORRIED ABOUT VOLUME,STOCK PUMP AND STOCK LINES.
DOES ANYBODY RUN AN ELEC. PUMP AND IF SO WHAT KIND,OR DOES ANYBODY KNOW OF A GOOD HIGH PER. MECH. PUMP.

I'm running a electric pump on my boat, but because it has zero hours, I can't really speak much about the application. I've heard of people burning up the electrics when they don't use a return line, so that's something to consider. I believe that the mechanical pumps are something special and that you just can't swap on a hi-po one. There are a couple of threads on this topic in the tech section, so try a search. You may just find a answer to your question. I sure wouldn't run your engine long in this condition as you run the risk of damaging it.

BTW-I assume that you've checked the obvious like a kinked line or clogged filter.

I run Magna Flow 280 gph electric pumps with return lines.I had a 89 Convincer and the gas tank already had extra holes for return systems.On my new boat I had to install bulkhead fittings.

OHHHHHHHHHHHHH , you had better give that thing some fuel!! Go 1/2" fuel line from the tank back, and a higher volume fuel filter/seperator & fuel pump, at least 140gph.

Kenny,
I went thru the same problem , except I bought a Hi volume mech pump that replaced the stock one or so Cpperformance told me(still a little ticked about that) well thinking that I had sufficient fuel pressure it was the last thing I checked in trying to diagnose my problem . Motor had made 625HP (502) on dyno but wouldn't spin more than a 21 p prop. Well by the time I check fuel pressure (it wouldn't even keep float bowls full) it was too late and I busted a piston.

Now I run a Mallory 180gpm electric, at the time I think it was the highest capacity without a return line.

26Scarab, Went thru 4 Mallory 180's in 1 season,pumps and regulaters took a **** . Have been running Magna Flows for 3 years.you need to run return lines so the pump does'nt dead head and it also helps keep the pump cool.

THANKS GUYS, BUT ARE THESE ELEC. PUMPS THAT YOU ARE TALKING ABOUT ( MAGNA FLOW,MALLORY ) MADE FOR MARINE,OR RACE CARS.ALSO DO I DO AWAY WITH THE STOCK PUMP OR RUN A TEE INLINE WITH IT.I SEE NOBODY SAID ANYTHING ABOUT HOLLEY ELEC. PUMPS IS THIS BECAUSE THEY DONT MAKE MARINE PUMPS OR IS THERE A PROBLEM WITH THEM.

A friend runs mechanical pumps on a 800hp blown 540 inch motor. They are marine pumps, with diaphragm vent tubes and everything. He has no fuel supply problems but he does run 1/2" lines.

I'll try to find out who makes the pumps (they are polished).

You can by mechanicle marine pumps but I don't think that they are designed to run on the seawater pump! I believe you will have to run on the block if it has a fuel pump boss. I would check with Summit or JEG'S.
I have a 520horse 502ci that I run a Mallory marine electric pump with regulator and have had good luck with it, ran a Holley before and had problems and then it died!
I know that a 540ci making as much power as yours needs fuel! You should definetly be running 1/2" hose from the tank all the way. I ran 1/2" hose from the tank to the Electric pump and then #8 braided stainless from the pump to a high volume filter/seperator that I got from Eddie Marine. I then have #8 stainless to the regulator and a #6 line going to each fuel bowl from there.

Brian41,
4 pumps in one season ? that sucks. I understand about the deadheading thing but I can't plumb a return line without cutting out the tank and welding a bung in it. So far I've been lucky (66hrs) on the Mallory.

You can run Mech pumps only if you have a boss on your block , a friend of mine has some Nascar stuff on his 565's