Holley EFI 300-621-100K Ultra Lo-Ram Intake Manifold Kit with Throttle Body Injectors - LS1 102mm and 100lb

The Holley EFI 300-621-100K is a complete Ultra Lo-Ram intake manifold kit for GM LS1/LS2/LS6 cathedral port engines, bundled with a 102mm throttle body and 100 lb/hr fuel injectors for a ready-to-run forced induction solution. Engineered for turbocharged and centrifugally supercharged applications, this kit delivers everything needed to build a high-performance LS induction system in a remarkably low-profile package.

The front-feed plenum design keeps overall manifold height to a minimum, allowing fitment under stock or mildly modified hoods. The modular construction supports custom throttle body positioning and inlet duct fabrication, making it ideal for tight engine bay builds and dedicated race applications.

Key Features:

• Designed for GM LS Gen III and IV engines with LS1/LS2/LS6 cathedral port cylinder heads — OE or aftermarket
• Ultra low-profile front-feed plenum optimized for turbocharged and centrifugally supercharged engines
• Peak power band at 7,000–8,000 RPM under forced induction
• Cast aluminum construction with satin natural finish
• Includes 102mm throttle body for maximum airflow
• Includes 100 lb/hr fuel injectors for high-horsepower fueling demands
• High-volume fuel rails with -8 AN (3/4 in.-16) O-ring ports and mounting hardware
• Fuel rail kit includes two bracket sets — one for long (standard) injectors and one for short (Pico/LS7) injectors
• Clears 4th Gen Camaro and C5 Corvette cowls and hoods without modification
• Front entry plenum flange allows fabrication of custom throttle body adapters and inlet ducts
• Plenum top mounting flange height: 5.17 in.; front-feed configuration height: 6.86 in.
• Legal for use on uncontrolled (non-emissions controlled) vehicles

The Holley EFI 300-621-100K is the ideal starting point for high-horsepower LS builds where hood clearance is a concern and maximum forced induction performance is the goal. The included 102mm throttle body and 100 lb/hr injectors eliminate the need for separate component sourcing, streamlining your build.