Holley 150 Black Pump

[Nazty]

I have a 540 naturally aspirated engine - 750 HP. Dead head regulator. Will a Holley 150 Black Pump support this?

[Danny Cabral]

I have a 540 naturally aspirated engine - 750 HP. Dead head regulator. Will a Holley 150 Black Pump support this?

http://documents.holley.com/holleyfu...ems_chart1.pdf (Fuel Systems Selection Chart)
https://www.holley.com/products/fuel...s/parts/12-150 (Holley 12-150 HP Fuel Pump)

[Nazty]

Put my new 150 Black pump & regulator in yesterday. Pressure started at 6 psi, then dropped to 3. I adjusted to 6 again, dropped to 4, so I adjusted again. Adjusted with motor running. Holley 1050 carb - 540 pump gas motor. Is this normal? Also, regulator is almost wide open.

[Danny Cabral]

Adjusted with motor running. Also, regulator is almost wide open.

No, that's not normal. Where is the electric fuel pump located? Is there a pickup tube/cavitation problem? What gauge are you using? Is this a return style fuel pressure regulator?

[Nazty]

There's a half inch pickup tube, and it's not a return style. Holley 12-803 regulator. I inspected the whole system for restrictions or sucking air.

[Danny Cabral]

There's a half inch pickup tube, and it's not a return style. 803 regulator. I inspected the whole system for restrictions or sucking air.

If I remember correctly, a dead-head fuel pressure regulator must be actually flowing fuel to properly adjust it. Meaning, the needle & seat has to be filling the fuel bowl, in order to set the flowing fuel pressure. Someone correct me if I'm wrong.
When I was carbureted, I always used a fuel pressure regulator; you want consistent fuel pressure. Furthermore, I've only used return style fuel pressure regulators, even when I was carbureted (Holley 12-803BP).

Also, I realize you're using the included Holley 12-803 FPR. However, it only has a .220" (7/32") restriction, and will not feed a big block high performance engine. The Holley 12-803BP is a great bypass type FPR. It has a .312" (5/16") restriction, which will feed a higher horsepower street engine much better than the Holley 12-803 FPR. If you want to use a good dead-head type FPR, then you need the Holley 12-704 FPR with its .437" (7/16") restriction, or other Holley high flow capacity FPR (LINK).

I hate to be the bearer of bad news, but I think you're making a big mistake by using that small Holley fuel pressure regulator, included with that nice Holley fuel pump.
The Holley 12-150 (black) HP Fuel Pump will support your horsepower (LINK), but the Holley 12-803 fuel pressure regulator has no place on a 750 horsepower engine.

UPDATE: Holley now offers the HP Billet & Dominator Billet line of carburetor & EFI fuel pressure regulators. These new fuel pressure regulators are what I would use.
http://documents.holley.com/holleyfu...ems_chart1.pdf (Fuel System Selection Chart) Find your fuel pump, then scroll to the right for the compatible FPR.
http://documents.holley.com/flyer_ho...el_systems.pdf (Holley Fuel Systems Catalog) Detailed information about all of Holley's fuel system components.

[Camaromeo]

If I remember correctly, a dead-head fuel pressure regulator must be actually flowing fuel to properly adjust it. Meaning, the needle & seat has to be filling the fuel bowl, in order to set the flowing fuel pressure. Someone correct me if I'm wrong.
When I was carbureted, I always used a fuel pressure regulator; you want consistent fuel pressure. Furthermore, I've only used return style fuel pressure regulators, even when I was carbureted (Holley 12-803BP).

Also, I realize you're using the included Holley 12-803 FPR. However, it only has a .220" (7/32") restriction, and will not feed a big block high performance engine. The Holley 12-803BP is a great bypass type FPR. It has a .312" (5/16") restriction, which will feed a higher horsepower street engine much better than the Holley 12-803 FPR. If you want to use a good dead-head type FPR, then you need the Holley 12-704 FPR with its .437" (7/16") restriction, or other Holley high flow capacity FPR (LINK).

I hate to be the bearer of bad news, but I think you're making a big mistake by using that small Holley fuel pressure regulator, included with that nice Holley fuel pump.
The Holley 12-150 (black) HP Fuel Pump will support your horsepower (LINK), but the Holley 12-803 fuel pressure regulator has no place on a 750 horsepower engine.

UPDATE: Holley now offers the HP Billet & Dominator Billet line of carburetor & EFI fuel pressure regulators. These new fuel pressure regulators are what I would use.
http://documents.holley.com/holleyfu...ems_chart1.pdf (Fuel System Selection Chart) Find your fuel pump, then scroll to the right for the compatible FPR.
http://documents.holley.com/flyer_ho...el_systems.pdf (Holley Fuel Systems Catalog) Detailed information about all of Holley's fuel system components.

I'll ask here, so maybe other can follow or read. Does anyone have any idea about the HP rating of the Holley billet regulator 12-840?
Do you maybe also know the internal orifice size? It is the one you posted as "update".

The Holley PDF you posted says the regulator 12-803 (cast) and also the 12-840 (billet) both work up to 750 HP, is that realistic?

My engine is (will be) a 496 BBC with 670 HP, so a little less compared to the OP's 540 with 750 HP.

My fuel system from tank to carb will be:
3/8" hard line from tank -> 100 micron 3/8" barb Earl's performance inline fuel filter -> 130 GPH 10 psi Edelbrock Victor fuel pump ->
-> 10 micron 3/8" barb Earl performance inline fuel filter -> Holley 12-840 regulator -> mounted using just one outlet side into a Holley 850 DP with dual hardline merging into one single inlet.

Do you think thats OK? I only use straight barb connections, no 90° angles, not even 45°.