LS3 Rectangle Port Carburettor Non EFI Hi Rise Single Plane Intake Manifold

Convert your GM LS engine from EFI to a dedicated carburettor setup with this Aeroflow Performance hi-rise intake manifold. Designed to deliver steady, even air and fuel distribution at high rpm, it’s the perfect retrofit for large displacement builds that run a 4150 square-bore carburettor.

Key features

• Hi-rise Single Plane design for high-rpm performance and improved velocity with large cubic inch engines
• Natural cast finish with a 4‑barrel 4150 square-bore carburettor pad
• Port size: 1.08" x 2.50"
• Overall height from carb pad to bottom of manifold: 171 mm (bonnet clearance should be checked)
• 5/16-18" carburettor studs (x4) for secure mounting
• Intake gasket: flat style ( Fel Pro 1222-2 or 1222-3 recommended)
• Includes: 10 x M6 x 1.00 mm hex screws (50 mm overall length) and 10 x M6 flat washers

Compatibility and fitment

• Designed for GM LS Gen III and IV engines equipped with LS3 rectangle port cylinder heads
• Suitable for carburetted, throttle body EFI, or port EFI configurations
• Non-EFI applications welcome; compatible with LS1/LS2 platforms as noted

Specifications at a glance

• RPM operating range: 3500–8000
• Finish: Natural Cast
• Single Plane configuration for focused mid-to-high rpm performance
• 4-bolt carburettor pad to accept aftermarket 4150 square-bore carbs with manual or electric choke

Designed to maximize air and fuel distribution efficiency in high-revving, large-displacement builds, this manifold is a purpose-built upgrade for LS3 rectangle port heads. Its hi-rise geometry helps clear restrictive clearest while delivering consistent manifold pressure across the cylinder bank. If you’re retrofitting to a carburettor setup, pair with the appropriate Fel Pro gasket and the included mounting hardware to streamline installation and maintain reliable sealing at high rpm.