joshh44

alright im building a 500+ hp 383 engine and im having troubles with the fuel pump. i know the stock fuel pump wouldnt give the engine enough fuel to the engine. what would be a good size? it will be carbed engine.
should i go electric or a mechanical one?
mechanical pumps are fairly cheap.
im also removing most of the electrial wires so should i leave the fuel pump relay and everything or remove it all and get a mechanical one?

joshh44

would a 130GPH pump be good?
i have no idea about the fuel pump department. need some help

Apeiron

130 GPH would be plenty of fuel. You could use an electric pump, or a mechanical one, or both.

joshh44

oh ok i found a holley mech. fuel pump for $74.99
and it says
free flow at 7.5-9 psi maximum. These pumps require a regulator.
what is a regulator? like what is it for?

i also found a 110GPH as well. would that be better for what im intending to do with the car?

Apeiron

The needle valve in a carburetor can't tolerate much more than 6 PSI or so, so a regulator is needed to keep the pressure from exceeding that. Some pumps have internal regulators, but some don't and need an external regulator. Regulators (internal and external) come in two flavors, internal-bypass and return. A return-style regulator is generally preferred.

joshh44

oh ok thanks so much for the infomation
ill do alittle more fuel pump shopping for my car.
would 130GPH pumps be the max i should get or should i try to get something that will pump more?

Apeiron

130 GPH is more than you'll ever need. That's enough to support around 1000 HP or so.

joshh44

holy wow!
i didnt think it can handle that much. im surpized.
well learn something everyday
thanks for the info! very much greatful, thank you

Apeiron

A naturally aspirated engine normally has a BSFC better than .6 lbs/HP/hr... 500 HP x .6 lbs/HP/hr = 300 lbs/hr of gasoline... 300 lbs/hr / 6.2 lbs/gallon = 48 gallons/hr.

One thing to watch out for though is that some pumps are flow-rated at 0 PSI instead of at operating pressure. Always better to choose a pump that's bigger than you need than one that's too small.

joshh44

thats what i was thinking. but i dont want to overkill with getting like a 160 pump or something. i seen them haha
i found some 80gph pumps for $50ish ill take a good look at the discriptions of the pumps and ask the local parts store about them so i get what i want.