LS1 Cathedral Port Carburettor Hi Rise Single Plane Intake Manifold

GM LS Cathedral Port Hi Rise 4-Barrel Carburettor Intake Manifold (Non-EFI)

Retro-fit your GM LS engine from EFI to a true 4150 square-bore carburettor with this Hi Rise Single Plane intake. Designed in the spirit of a Super Victor style manifold, it delivers a clean, steady air and fuel path for optimized high-rpm performance on LS1/LS2 cathedral port heads.

• Single Plane, Hi-Rise Performance: Engineered for high rpm and large displacement, keeping air and fuel moving consistently into the cylinders for strong throttle response and top-end power.
• 4150 Square-Bore Carburettor Pad: Accepts aftermarket 4-barrel square-bore carburettors with either manual or electric choke options.
• GM LS Cathedral Port Compatibility: Specifically designed for GM LS Gen III/IV engines equipped with LS1/LS2 cathedral port cylinder heads.
• Non-EFI Applications:Ideal for retro-fit carburettor setups, throttle-body EFI, or port EFI configurations.
• Gasket & Hardware Ready: Uses a flat-style intake gasket (Fel Pro 1312-2 or 1312-3 recommended). Supplied with 4 carburettor studs (5/16-18) and complete mounting hardware (10 M6 x 1.00mm hex screws and 10 M6 washers).
• Robust Build: Natural cast finish with a compact 4-bolt, square-bore flange to ensure reliable sealing and durability under high-load, high-RPM conditions.

Key Specifications

• Port Size: 1.08" x 2.50"
• Carburettor Pad: 4150 square-bore flange
• Overall Height (carb pad to bottom): 171 mm (bonnet clearance should be checked)
• RPM Operating Range: 3500 to 8000
• Includes Hardware: 4 x 5/16-18" carburettor studs, 10 x M6 x 1.00mm hex screws (50 mm UHL), 10 x M6 flat washers
• Gasket Recommendation: Flat gasket (Fel Pro 1312-2 or 1312-3)

What You’ll Achieve

With this hi-rise cathedral-port manifold, LS enthusiasts gain a stable, high-flow air delivery path that supports aggressive cam profiles and high-rPM operation. Its single-plane design minimizes plenum restrictions, helping your engine deliver smooth torque at higher revs while maintaining drivetrain usability for street-driven builds. The manifold’s non-EFI nature frees you to run a traditional carburettor setup or integrate with throttle-body or port EFI systems as your project evolves.

Fitment & Applications

• Fits GM LS1/LS2 cathedral port engines (Gen III/IV) using a 4150 square-bore carburettor pad.
• Suitable for retro-fit applications where a carburettor or hybrid EFI configuration is desired.
• Not OEM EFI; designed to replace EFI intake manifolds in appropriate LS cathedral port builds.

What’s Included

• Intake Manifold (Natural Cast Finish)
• 10 x M6 x 1.00mm Hex Screws (50 mm UHL)
• 10 x M6 Flat Washers
• 4 x 5/16-18" Carburettor Studs

Note: Check bonnet clearance due to the 171 mm overall height to ensure proper fitment under your hood. This manifold is ideal for hot-rod projects and performance builds where reliable carburettor-to-engine tuning is essential.