Spring Sleeve 3.50

The Spring Sleeve 3.50 from ALLSTAR PERFORMANCE is a professional-grade spring cup sleeve designed for high-performance engine builds and racing applications. This bolt-on upper sleeve accommodates 3.5-inch inner diameter spring cups, making it essential for custom valve spring assemblies in competition engines. Whether you're building a street performance engine or preparing a race motor, this precision component ensures proper spring seating and consistent valve train geometry under demanding conditions.

Manufactured from cadmium-plated steel, the Spring Sleeve 3.50 delivers durability and corrosion resistance essential for long-term engine reliability. The cadmium plating provides superior surface protection while maintaining precise dimensional tolerances critical to valve spring function. Its bolt-on design allows straightforward installation without requiring special tools or machine work, making it ideal for engine builders who demand both performance and practicality. The 3.5-inch inner diameter specification ensures compatibility with oversized spring cups commonly used in high-lift, high-RPM engine packages.

Engine builders, machine shops, and serious enthusiasts rely on ALLSTAR PERFORMANCE's Pro Series components to achieve repeatable results. The Spring Sleeve 3.50 is sold individually, allowing builders to source exactly the quantity needed for their project. Proper spring cup sleeves prevent valve spring binding and ensure consistent preload across the valve train, directly impacting engine longevity and performance stability. This component is an ideal match for custom builds using performance-grade valve springs and high-lift camshaft packages on small-block and big-block platforms.