Fwiw, I found the Holley red pump to be inadequate for my 500hp 502. On paper it calcs out, but I was barely getting 5psi at idle and it would drop to 3psi when I gunned it. The pump was mounted about level with the top of the tank.

Just a thought, Have you ever put an Amp meter on the pump while it's running just to check the draw. It would tell you if your relay and wires are the correct size and if something is putting excessive strain on the pump.

Holley Pumps have very little lift ability. Think back when they where designed....put a rear sump on your cars gas tank to feed it.

Speaking of which, all electric pumps are rated with gravity fed fuel.

Which is why if you run a pump, and it can't be mounted lower than the tank, it should be lower than the lines/fuel water seperator feeding it. Ie: bottom of the "trap" if you will.

Those Holley red/blue pumps are junk. Also, they don't support power. Right in Holley's catalog, its states, 425HP max on those pumps.

Fuel pump GPH ratings are mainly a sales tactic, and many do not flow what you think they flow.

If it were me, a basic 502 carb build, I'd get the merc seawater/fuel pump deal, and be done with it.

Yup.

Just think how many GPH a 3/8" hose connected to bottom of fuel tank would flow without a pump.

Thus why real world conditions are much different than some static ideal condition.

Go figure, today I go out to work on a boat that sat all winter. Port electric fuel pump doesn't make a noise, wires get a little warm. Damn pump was frozen. Removed the bottom plate broke the armature loose and runs fine now.

[ATTACH=CONFIG]540539[/ATTACH]

if I go that route will my seawaterpump bracket work? So all I will need is new seawater pump and fuel pump?