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 manifolds will work with OE or aftermarket cylinder heads. 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. 
The 300-621 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:

• Designed for GM LS Gen III and IV engines equipped with GM LS1/2/6 (cathedral cylinder heads
• Designed for forced induction (supercharged or turbocharged) engine applications with peak power at 7000-8000 rpm depending on the application.
• With forced-induction and the short runner length the engine rpm at which peak power occurs is more likely to be coupled to the supercharger or turbocharger being used
• Modular design allowing the use of front-feed plenum entry
• Intake design facilitates custom inlet duct and throttle body placement
• Low height to fit under a stock or mildly modified hood in the front configuration
• Front entry plenum flange allows design & fabrication of special throttle body adapters or inlet ducts for custom installations
• Clears 4th Gen Camaro and C5 Corvette cowls and hoods without modification
• High volume fuel rails and mounting hardware included with ¾”-16 o-ring ports (8 AN)