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Holley 12-803 Fuel Pressure Regulator, 2-Port, 4.5-9 PSI

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Holley 12-803 Fuel Pressure Regulator, 2-Port, 4.5-9 PSI
Holley

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#42712803

Holley 12-803 Fuel Pressure Regulator, 2-Port, 4.5-9 PSI

  • .220" (7/32") restriction
  • Regulator features 3/8" NPT in/out ports
  • Fuel pump regulator works well with Holley high performance fuel pumps
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$46.76

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$51.95

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Product Summary

Universal Fit, 4.5-9 Fuel Pressure Rating (psi), Steel

  • .220" (7/32") restriction
  • Regulator features 3/8" NPT in/out ports
  • Fuel pump regulator works well with Holley high performance fuel pumps
  • Flash chromed steel
  • All Holley regulators are pre-set at the factory so there is no guesswork when first installing the regulator

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Key Specs

MFG. Part #12-803
BrandHolley
Regulator StyleNon-return
Material TypeSteel
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Holley 12-803 Details

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 12-803 fuel pressure regulator features 3/8" NPT in/out ports.

  • Adjustable fuel regulation from 4-1/2 to 9 psi
  • .220" (7/32") restriction
  • 3/8" NPT ports ( 1 in, 2 out)
  • Chrome finish
  • Mounting bracket included

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Holley Heritage Sale 10% off Select Parts

Holley Heritage Sale 10% off Select Parts

Holley Heritage 10% Off Select Parts Sale, running from July 6, 2026, through July 31, 2026. For a limited time, customers can save 10% off on select parts, making it the perfect opportunity to upgrade your vehicle with high-quality components. Sale prices apply to purchases made during the sale period only. No rainchecks or exceptions will be provided. This sale cannot be combined with any other offers, discounts, or promotions.

Holley 12-803 Specifications

KEY SPECS
MFG. Part #12-803
BrandHolley
Regulator StyleNon-return
Material TypeSteel
GENERAL
Fuel Pressure Rating (psi)4.5-9
Pressure Regulator Inlet Size3/8" NPT
Pressure Regulator Outlet Size3/8" NPT
Inlet Quantity1
Outlet Quantity2
Mounting Hardware IncludedYes
Includes Mounting Bracket(s)Yes
Fittings IncludedNo
Sold in QuantityEach
GTIN Code090127020227

Ratings & Reviews

4.8

18 Reviews

Overall Assessment

Customers highly rate our product for its reliable performance, ease of use, and excellent quality. It effectively regulates fuel pump pressure, holding it precisely at 6 PSI regardless of temperature. The sturdy, high-quality design fits well with various setups and adjustments are simple. Users recommend it especially when switching to a carburetor or breaking in a new engine. Despite being a robust and efficient solution to fuel pressure problems, the product is priced reasonably. Some users found that additional steps like getting threads tapped were required, but overall satisfaction with the product performance is high.

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4.8

18 reviews

5

15

4

2

3

1

2

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1

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Most Liked Positive Review

4.0

No problem with the product

Once opened the box and reading the instructions it said that the regular is not to be used with mechanical fuel pumps which I have. I did not see this info on the online details of this regular when I ordered it. I ordered it due to the Edelbrock carb requires 6 psi or less

Most Liked Negative Review

3.0

Maybe

Need to get the threads tapped to use it

Filter by Ratings

I would buy from them again but don't need to.

5.0

6 months ago

Bill N.

Las Vegas, NV

Verified

It did what it's supposed to and had the correct fuel pressure rating

Would Recommend

Does the job, but will leak due to new fuels over time

4.0

6 months ago

RM

California

Verified

Like the title says, this will do the job, just be prepared to buy a new diaphragm after a year or so. Today's fuels wreak havoc on the gasket material.

Would Recommend

Nicer looking piece than I expected

5.0

a year ago

RS

Box Elder SD

Verified

This is a quality regulator. Nice shiney piece for the engine compartment.

Would Recommend

Great product

5.0

2 years ago

None

Lancaster, KS

Verified

This part was installed on a 1947 Ford Ratrod. It has a 421 sbc in it with tunnel ram and 2 450 Holley carbs.

Would Recommend

Great product. Nice fit and finish.

5.0

3 years ago

Allen S

Wadena MN

Verified

Used it because the new fuel pump was putting out 15lbs. Worked great.

Would Recommend

No problem with the product

4.0

3 years ago

Anthony

Santa Maria CA.

Verified

Once opened the box and reading the instructions it said that the regular is not to be used with mechanical fuel pumps which I have. I did not see this info on the online details of this regular when I ordered it. I ordered it due to the Edelbrock carb requires 6 psi or less

Would Recommend

Meets both Holle0y and Speedway's high standards

5.0

4 years ago

Drifter

Virginia beach

Verified

Holds pressure precisely at 6 PSI recommended by Edelbrock no fluctuation hot or cold that was exactly what I had hoped

Would Recommend

I would buy this again as it did it's job.

5.0

4 years ago

Ken

Cokato, MN

Verified

I needed to cut my gasoline pressure from electric fuel pump and this product worked perfectly.

Would Recommend

Regulators

5.0

5 years ago

Rickter

Lakewood Colorado

Verified

Easy to and adjust when used with gauge

Would Recommend

Yes

5.0

6 years ago

DJ

Lake Charles, Louisiana

Verified

Fits well with speedway gauge, no leaks, preset @6psi.

Would Recommend

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Questions & Answers

11 Questions • 11 Answers

Can this regulator be turned down to 2 psi

by Jerry

• a month ago

1 answer

View Answer

Does this come with a gauge and if not what would be the recommended gauge to get?

by Trenton Davis

• 8 years ago

2 answers

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At what setting is the regulator pre-set coming out the box?

by HEVS

• 8 years ago

1 answer

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Does it matter which port I install a guage on? And where can I get the adapter to run a guage on it?

by Shaine

• 9 years ago

1 answer

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I have a 89 chevy truck with a 350. Has factory electric fuel pump and tank. The fuel injection has been changed to a 4 barrel intake with a holley 4 barrel is there a pressure regulator that I can use to get my pressure down to what I need to run it without it flooding.

by Kuntry boy

• 11 years ago

1 answer

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What is the max inlet psi on this regulator

by Kuntry boy

• 11 years ago

1 answer

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Can this be used on a single feed carb?

by Racin

• 11 years ago

1 answer

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Can I run e85 throw this reg

by Jamesluck

• 12 years ago

1 answer

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Does this regulator have a return?

by Openlatte

• 12 years ago

1 answer

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Can this pump be used with a mamual fuel pump

by kevo

• 13 years ago

1 answer

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