SKU: 84400020799

Holley Diecast In-Tank RetroFit Fuel Module Returnless System - 12-158

Sale price$382.48 Regular price$424.98
Save 10%

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Jul 9 - Jul 14

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

Description

Holley Diecast In-Tank RetroFit Fuel Module Returnless System - 12-158Overview: Are you interested in an EFI retrofit kit, but just can't get past the complication of the fuel system? Holley is proud to introduce their Universal In Tank Retrofit Fuel Modules! Available in return and returnless versions, you can rest assured Holley has the solution you need for your EFI fuel pump woes. Now you can convert your factory tank or fuel cell to an in tank EFI fuel system quickly and easily! And add the benefits of a Holley

Overview:

Are you interested in an EFI retrofit kit, but just can't get past the complication of the fuel system? Holley is proud to introduce their Universal In-Tank Retrofit Fuel Modules! Available in return and returnless versions, you can rest assured Holley has the solution you need for your EFI fuel pump woes. Now you can convert your factory tank or fuel cell to an in-tank EFI fuel system quickly and easily! And- add the benefits of a Holley Hydramat in the process! The conversion is easily accomplished with basic tools and requires no welding or fabrication. The aluminum module design includes a die cast pump hanger bracket to control pump vibration while also providing a low profile design to fit where space is at a premium. Holley's innovative clamping system and integrated fuel pump makes it easy. Once installed, hook up your fuel lines and your power source/ground and you're off and running! NO hassle! Supports up to 550 EFI or 700 Carb HP (@ 60 PSI at 13.5 Volts / 10.4 AMP Draw) Of course there are many variables, estimates are based on gasoline. Individual systems will vary based on fuel system design, regulator type, fuel cell location, etc...

Features:

  • The easiest way to convert your vehicle to an in-tank, EFI fuel system
  • Installs in any fuel tank from 7” to 12” deep to fit a wide variety of applications
  • The low profile design is only 1.275" thick above the tank mounting surface for added clearance when needed
  • The innovative clamping system allows you to locate the module anywhere in the tank beside your existing sending unit
  • The clamping system allows you to rotate the unit 360 degrees for easier clocking of the plumbing and wiring locations under your ride
  • Includes innovative Holley Hydramat to ensure consistent fuel supply. The 3” x 15” HydraMat mounting flange has 6 clocking pin locations to allow for 360 degree adjustment to clear sending unit levels or any tank floor restrictions that you might encoun
  • Die cast aluminum construction for corrosion resistance and long lasting good looks
  • ¼” NPT ports for a wide variety of plumbing options
  • Ideal for Terminator EFI, Sniper EFI, MSD Atomic EFI or any TBI of EFI conversion
  • Optional roll over valve available
  • Two different fuel pumps are available to match your requirements - 255LPH or 400LPH for both return and returnless style systems

Application:

Year Make Model Submodel Engine Size
Universal

Specs:

Application Universal
Brand Holley
Diameter 4.8"
Emission Code 3
Free Flow LPH 255
Material Die Cast Aluminum
NPT Thread 1/4 NPT
Product Type Fuel Pump Module
Warning California Proposition 65
Warranty Limited 90 Day
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 84400020799

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.4 ★★★★★
Based on 785 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
T
Verified Purchase
Thrifty Tiffy
Boise, US
★★★★★ 4
Nice for the price
Size: Medium, Color: B004
I really like the LALESTE Women’s Boyshort Underwear overall! They’re super comfortable, soft, and have great full coverage—perfect for everyday wear. The material feels stretchy and smooth, and they stay in place without digging in or riding up. Definitely a solid option if you like a more covered, secure fit. My only downside is that they are a bit too high-rise for my personal preference. They come up higher than I expected, so if you prefer a lower-rise fit, just keep that in mind. Other than that, the quality and comfort are great, and I still find myself reaching for them often!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 23, 2026
A
Verified Purchase
Ash
Fort Morgan, US
★★★★★ 5
Love them
Size: X-Large, Color: B004
Love them! Super comfortable, love the design and stretchiness!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 20, 2026
J
Verified Purchase
J. Howard
Grantham, US
★★★★★ 5
Comfy and wash well
Size: XX-Large, Color: B004
Very comfortable and breathable; wash and dry well in machines, no shrinkage. Good quality and value.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 28, 2026
A
Verified Purchase
Amazon Customer
Cuba, US
★★★★★ 3
Soft but easily rolls down
Size: X-Large, Color: B004
Comfortable and soft but it kept sliding down, I have a longer torso so that could be why, but I couldn’t get it to stay up, it would constantly roll into my C-section scar
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 1, 2026
P
Verified Purchase
Payton
Charlottesville, US
★★★★★ 5
Perfect for whatever activity!
Size: Large, Color: B004
I bought these specifically for my postpartum journey, and I still wear them. They are so comfy & a perfect length.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 16, 2026

recommand products