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Holley

Holley 12-803BP Carbureted Bypass Fuel Pressure Regulator

Based on 156 reviews
Condition: New
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$144.94

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Availability: In Stock.
Fulfilled by Amazon
Arrives Wednesday, Nov 18
Order within 19 hours and 52 minutes

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At a glance

Condition
New
Model
12-803BP
Dimensions
3.5 x 3.5 x 2.5 in
Weight
9.6 oz
Material
Aluminum
Fit Type
Universal Fit
Vehicle Service Type
Car
In the box
Holley Carbureted By-Pass Regulator

Features 8

  • Adjustable fuel regulation from 4-1/2 to 9 psi
  • Preset to 7psi
  • 3/8 NPT ports (1 in, 1 out, 1 bypass or return)
  • Used in systems with a return line back to the fuel tank

Description

Holley fuel pressure regulators are designed to precisely control the fuel pressure from the fuel pump to the carburetor. Too much fuel pressure for a given needle and seat assembly can overload the needle and seat and may cause flooding or drivability problems. Each Holley fuel pressure regulator is fully adjustable so regulating the fuel pressure to your engines needs is a simple task. All Holley regulators are pre-set at the factory so there is no guesswork when first installing the regulator. The Holley 12-803BP fuel pressure regulator features 3/8" NPT in/out ports and a 3/8" NPT return port.

Specs 34

Brand Holley
Fit Type Universal Fit
Vehicle Service Type Car
Item dimensions L x W x H 3.5 x 3.5 x 2.5 inches
Material Aluminum
Compatible with Vehicle Type Car
Auto Part Position Rear
Outlet Connection Type Threaded (NPT)

Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Wednesday, Nov 18

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

WORKS
The bypass type regulator works on my 2001 chevy blazer with the stock electric fuel pump in tank. Mounted this on the frame next to the filter. Used brass 90s and strait hose barbs to complete the job.
Reviewed in the United States on March 26, 2025 by Shawn
Appearance..!
Review Image by Arnie
Just installed it, getting ready to fire it up! Looks good, but will tell later if any issues come up!
Reviewed in the United States on June 4, 2026 by Arnie
Nice Regulator
I put a 280ZX engine in my 240Z and the new engine is not set up for the original mechanical fuel pump so I had to install an electric fuel pump. The electric pump puts out too many PSI for the carburetor so I needed the regulator to be able to control the PSI of the fuel to the carburetor. This regulator works great. Highly recommend it. ... show more
Reviewed in the United States on February 22, 2014 by Billy Bob
No threaded holes
Review Image by Haidyn
Review Image by Haidyn
Mounting holes not threaded how am I supposed to install without threaded holes? For triple the price of a Amazon brand that has threaded holes i was expecting good quality
Reviewed in the United States on April 16, 2026 by Haidyn
Worth it!
I redid the entire fuel system on my 89 F150 carbonated 351W rebuild, this was an intricate piece that worked great.
Reviewed in the United States on December 19, 2019 by Pernarosa
I like it and it works but 3/8 ports are way ...
I like it and it works but 3/8 ports are way too big. Who needs that much fuel? Would much rather have 1/8 NPT ports so normal 1/4 through 3/8 fuel line fittings work. 3/8 ports are crazy and just make me find special fittings. I used it for a weber carb on a cj7 and removed the old split fuel filter. Now fuel pressure is rock solid ... show more
Reviewed in the United States on July 19, 2015 by chris
fully adjustable, we are running a high pressure pump ...
fully adjustable, we are running a high pressure pump in tank and needed a regulator for carburetor . Using a fuel pressure gauge we dialed it down to 6.5 lbs and it keeps fuel pressure exactly where we set it.
Reviewed in the United States on December 4, 2016 by Mike Hall
Great bypass regulator
Great affordable regulator
Reviewed in the United States on July 21, 2022 by Brian K Marquette
How it works
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