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PART# 300-631

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The P/N 300-631 & 300-631BK Lo-Ram billet aluminum plenum tops are designed as part of the Holley LS front-feed Lo-Ram EFI intake manifold kits. It is commonly known billet is the best. The strength and rigidity of these components is impervious to cracking and further resists any vibration and harmonics. These 3D CNC machined pieces are cut from a solid block of billet and then anodized. Take your Lo-Ram to another lever with Holley billet Lo-Ram components.


  • Machined billet construction
  • Clear/black anodized for long-term protection from elements and fuels
  • Works with all front feed Lo-Ram bases (300-602, 300-602BK, 300-603, 300-603BK)
  • Holley Lo-Ram Plenum top can be custom machined for a standard “large” 6-1/8” x 3-1/8” burst panel (SFI approved burst panels, burst panel frame sets, and gaskets may be purchased from various manufacturers such as Allstar Performance or Specialty Fastene
  • Modular Lo-Ram design allows user customization for your induction system
  • Flange seal o-ring cord and the mounting fasteners are included in the kit
  • Includes hardware


BrandHolley EFI
Emission Code3
EngineGM LS1/LS2/LS6
Fuel System TypeEFI
Manifold TypeLo-Ram
Product TypePlenum Top
WarrantyLimited 90 Day
Part Number300-631



This part is legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles and Racing Use Only Vehicles.

The following vehicles are considered Uncontrolled (Non-Emissions Controlled) Vehicles:

  • 1965 and older U.S. manufactured California Certified vehicles
  • 1967 and older U.S. manufactured Federally Certified vehicles
  • 1967 and older Foreign manufactured vehicle

The following vehicles are considered Racing Use Only Vehicles:

  • Racing Use Only Vehicles are vehicles that are used exclusively for competition and that are not registered and that may never be used on the street

WARNING: It is against the law to install this part on an Emissions Controlled Vehicle

The following vehicles are considered Emissions Controlled Vehicles:

  • 1966 and newer U.S. manufactured California Certified vehicles
  • 1968 and newer U.S. manufactured Federally Certified vehicles
  • 1968 and newer Foreign manufactured vehicle

Tech Resources

Warranty Information

Limited 90 Day: See Details

*Free Shipping & Handling only offered to the contiguous US on orders over $100, excludes clearance parts and oversized packages.

Some parts are not legal for use in California or other states with similar regulations.

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