Intake Manifold for Pontiac Firebird (1998-2002) Cathedral Port Black w/Fuel Rail EFI

High-Flow Aluminum Intake Manifold for 1998-2002 Pontiac Firebird (LS1 / F-Body)

What it does: Replaces the restrictive factory composite intake manifold with a high-flow aluminum single-plane design to support significant horsepower increases in EFI applications up to 7,000 RPM.

The Stock Firebird Composite Intake Limitations

The factory LS1 polymer intake manifold, while adequate for stock power levels and low-end torque, becomes a major restriction when dealing with aggressive cam profiles, higher displacement, or forced induction. The long-runner design of the OEM Gen III small block manifold severely chokes airflow past 5,500 RPM, capping high-RPM horsepower potential. Additionally, factory composite manifolds are susceptible to stress cracking over time under high boost or elevated engine bay temperatures, leading to unmetered vacuum leaks, lean conditions, and inconsistent manifold absolute pressure (MAP) readings.

The Engineering Solution

This satin aluminum single-plane intake manifold is engineered specifically for cathedral port LS1, LS2, and LS6 cylinder heads, shifting the effective powerband to a broader 2,500-7,000 RPM range. Designed to accept a 4150 square bore throttle body, it dramatically increases plenum volume and runner flow cross-section (port size 2.50" H x 1.15" W), ensuring cylinder fill remains volumetrically efficient at high engine speeds. Constructed from heat-dissipating cast aluminum and finished in a stealth black coating, it eliminates the structural flexing found in OEM plastics under heavy manifold pressure. The included high-capacity fuel rails guarantee adequate fuel delivery for high-demand EFI systems, making this the definitive induction upgrade for max-effort F-Body builds.

Technical Specifications

Compatibility

• 1998-2002 Pontiac Firebird (5.7L LS1)
• GM LS1 Engines (Cathedral Port)
• GM LS2 Engines (Cathedral Port)
• GM LS6 Engines (Cathedral Port)

The Pontiac Performance Caliber

Built for the high-RPM demands of track-dedicated F-Body platforms, this manifold delivers the sustained top-end horsepower, structural durability, and raw induction volume required for serious modern muscle car performance.