Product Description
Michigan Motorsports 1.89"/1.55" Stainless High Performance Valve Set – Cathedral Port LS
Fits 1999–2006 706 & 862 Cathedral Port Heads | LM7 L59 LR4 LM4 | Direct Drop-In Upgrade
Upgrade your factory LS cathedral port cylinder heads with the Michigan Motorsports 1.890"/1.550" Stainless High Performance Valve Set. Designed as a direct drop-in replacement for 1999–2006 706 and 862 casting heads, these valves are built from high-strength 21-4N stainless alloy for superior durability under high RPM and elevated cylinder temperatures. Featuring hard chrome plated stems, hardened tips, undercut stems, and swirl polishing, this set improves airflow over OEM GM valves and standard replacements while maintaining factory fitment. Perfect for refreshed stock builds or performance-oriented street applications.
Key Features & Benefits
- High-Strength 21-4N Stainless Construction – Manufactured from premium 21-4N stainless alloy for improved heat resistance and durability compared to stock GM valves, ideal for performance and heavy-duty use.
- One-Piece Forged Design – Precision one-piece forgings eliminate weak points, providing added strength and reliability in high RPM LS applications.
- Flow-Improving Undercut & Swirl Polished Stems – Undercut stems and swirl polishing enhance airflow over OEM GM and standard aftermarket valves, supporting improved cylinder head efficiency.
- Hardened Tips & Hard Chrome Plated Stems – Chrome plated stems reduce wear in valve guides while hardened tips provide added protection against rocker arm and valvetrain contact.
- Complete 16-Valve Set – Includes 8 x 1.890" intake valves and 8 x 1.550" exhaust valves, designed as a direct drop-in replacement for factory LS cathedral port head applications listed below.
Key Fitments
- 1999–2006 GM LS Cathedral Port Heads – Casting Numbers 706 and 862.
- Engine Codes LM7, L59, LR4, LM4 – Direct replacement for factory 1.890" intake and 1.550" exhaust valve configurations.
- Stock & Mild Performance Builds – Ideal for refreshed factory heads or airflow-focused upgrades without changing valve sizing.
