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Holley EFI

Plenum top for Ultra Lo-Ram 300-621BK

Black Finish

Part # 300-604BK
In Stock
Your Price
$173.95
Suggested Retail
$194.00
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The Holley LS1/2/6 Ultra Lo-Ram intake manifold kits are designed for GM LS Gen III and IV engines equipped with GM LS1/2/6 (cathedral port) cylinder heads. These intake manifold and rail kits will work with OE or aftermarket cylinder heads. The 300-604 is the plenum top in the 300-621BK complete kit. Offering this separately allows you to select your components individually as you build your system. The Ultra Lo-Ram intake manifolds are designed for forced induction (supercharged or turbocharged) engine applications and the 105 mm throttle body part number 112-581 or similar models. The base intake manifold is designed with a lower overall height to fit under a stock or mildly modified hood in the front-feed configuration. The 300-621 Ultra Lo-Ram plenum entry was configured to provide a very low profile modular intake manifold suitable for turbocharged or centrifugally supercharged engines. The fuel rail kits come with two sets of brackets. A set for long (usually standard length) fuel injectors and a set for short (such as Pico, or LS7) fuel injectors.

Features:

  • Individual plenum top for 300-621BK allows you to select your components individually as you build your intake system
  • Designed for GM LS Gen III and IV engines equipped with GM LS1/2/6 (cathedral port) cylinder heads
  • Designed for forced induction (supercharged or turbocharged) engine applications with peak power at 7000-8000 rpm depending on the application
  • Modular design allowing the use of the included front plenum entry
  • Intake design facilitates custom inlet duct and throttle body placement
  • Low height to fit under a stock or mildly modified hood.
  • Front entry plenum flange allows design & fabrication of special throttle body adapters or inlet ducts for custom installations
  • Clears 1998-2002 (4th Gen) Camaro/Firebird and 1997-2004 (C5) Corvette cowls and hoods without modification
  • High volume fuel rails and mounting hardware included with ¾”-16 o-ring ports (8 AN)

About Holley EFI

Holley is the new standard in EFI! Whether you're engine swapping your classic car or need to manage 4000 horsepower in your twin-turbocharged drag radial race car, Holley EFI has the solutions you need to get your project up and running better than ever!

BrandHolley EFI
ColorBlack
Emission Code3
EngineGM LS1/LS2/LS6
FinishCast
Fuel System TypeEFI
Manifold TypeUltra Lo-Ram
Product TypeIntake Manifold Top
WarrantyLimited 90 Day
UPC090127079461
Part Number300-604BK
3

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
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.