Repl Cyl Sleeve SBC 3.970 Bore 4.254 OD

The Replacement Cylinder Sleeve SBC 3.970 Bore 4.254 OD from DARTON SLEEVES is a precision-engineered iron sleeve designed for small block Chevy engine rebuilds and performance modifications. When engine wear, scoring, or damage compromises cylinder wall integrity, a quality sleeve restores the block to serviceable condition without requiring complete replacement—a cost-effective solution for enthusiasts and professional builders who demand reliability and longevity from their rebuilt powerplants.

Manufactured from durable cast iron, this sleeve features a 3.970-inch bore diameter, 4.254-inch outer diameter, and 6.000-inch height with a 0.142-inch wall thickness. The specified dimensions allow proper ring seal, piston clearance, and oil retention while maintaining structural rigidity under combustion pressures and thermal cycling. Darton's proven sleeve design accommodates both stock and high-revving applications, making it suitable for street engines, weekend track builds, and competitive platforms that require cylinder wall protection and straightness.

This sleeve is ideal for engine builders restoring worn small block Chevy cores or upgrading to performance specifications. Installation requires proper honing and precise bore alignment to ensure concentricity and eliminate piston-to-wall contact. The 3.2-pound weight and compact dimensions simplify handling during block machining and assembly. Whether you're freshening a daily-driver 350 or constructing a competition engine, this replacement cylinder sleeve delivers the dimensional accuracy and material quality necessary for a solid, long-lasting rebuild.