Holley 300-964 Hi-Ram EFI Intake Manifold Kit Big Block Chevy - 2x4 4150

The Holley 300-964 Hi-Ram EFI Intake Manifold Kit brings modern fuel injection technology to classic Big Block Chevy engines. Featuring a 2x4 4150 four-barrel throttle body plenum top, this cast aluminum manifold delivers a broad 1,500–8,000 RPM power band, making it equally capable on the street or at the strip. Included black anodized EFI fuel rails and a throttle cable bracket make this a complete, ready-to-install kit.

Built from cast 356-T6 aluminum with a natural, satin as-cast finish, the Hi-Ram is engineered as a cost-effective alternative to expensive fabricated sheet-metal or billet manifolds for high-performance applications where induction system height is not a concern. A modified hood will be required for most vehicle installations.

Key Features:

• Power Band: 1,500–8,000 RPM
• Plenum Top: 2x4 4150 four-barrel throttle body configuration
• Throttle Body Compatibility: Drive-by-wire or cable-actuated GM Gen IV LS 4-bolt throttle bodies
• Construction: Cast 356-T6 aluminum, natural satin as-cast finish
• Port Flange Openings: 2.40" tall x 1.60" wide; uses Mr. Gasket intake manifold gasket #5817
• Fuel Rails: Black anodized, machined for -10AN O-ring fittings — included in kit
• Plenum Top Gasket Type: 3/32" round O-ring cord
• MAP Sensor Port: GM Gen IV LS MAP sensor; plus provisions for (1) 1/8 NPT, (1) 1/4 NPT, and (1) 3/8 NPT fittings to the plenum
• Coolant Ports: Standard Chevy thermostat housing flange outlet; (2) 1/2 NPT and (1) 3/8 NPT coolant ports provided
• Distributor Compatibility: Requires early-type GM or small-cap MSD or Holley distributors — not compatible with HEI distributors
• Throttle Cable Bracket: Included
• Engine Compatibility: Designed for 1965 and later 396–502+ CID MKIV–MKVI standard 9.80" deck height Big Block Chevy engines with standard intake flange rectangle-port cylinder heads

The Hi-Ram series also works with aftermarket cylinder heads, provided they feature standard rectangle-port flange openings and bolt-hole locations. Manifold bolts should be torqued to 25 ft-lbs and re-torqued after initial heat cycling. Related Big Block Chevy Hi-Ram part numbers include 300-961 (base manifold only) and 300-963 (105mm single throttle body plenum top).