Features:

• Base manifold and rail kit for Ultra Low-Ram 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
• Intake design facilitates custom inlet duct and throttle body placement
• Low height to fit under a stock or mildly modified hood in the front-feed configuration
• 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)
• Manifold base can be used with 300-604 lid and the 300-606 throttle body adapter

About Holley EFI

Find standalone EFI for LS, Coyote, Hemi and more at Holley.com. From engine swapping to managing up to 4000 horsepower, we have a solution for every project!

• Gasket Kit, Hi-Ram Plenum O-Ring Cord

  Gasket Kit, Hi-Ram Plenum O-Ring Cord

  Part# 508-21

  $36.17

  Qty: 

  Add To Cart
• Intake Manifold Gasket Set, O-Ring LS1/2/6

  Intake Manifold Gasket Set, O-Ring LS1/2/6

  Part# 508-23

  $46.52

  Qty: 

  Add To Cart
• 105mm Throttle Cable Bracket For 300-621

  Lo-Ram Front-Feed Intake Manifold

  Part# 20-154

  $25.57

  Qty: 

  Add To Cart
• Plenum top for Ultra Lo-Ram 300-621

  Satin Finish

  Part# 300-604

  $90.63

  Qty: 

  Add To Cart
• Replacement Fuel Rail Kit For GM LS Series Lo-Ram Single Injector Manifolds

  Single Injector Design

  Part# 534-260

  Qty: 

  Add To Cart
• 105mm Throttle Body Adapter For Ultra Lo-Ram 300-621

  Front-feed mount with satin finish

  Part# 300-606

  Qty: 

  Add To Cart

This part is legal for sale and use on Uncontrolled (Non-Emissions Controlled) 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

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