Repl Cyl Sleeve SBC Bow Tie Block 4.120 Bore

The Darton Sleeves Replacement Cylinder Sleeve for Small Block Chevy Bow Tie Block (4.120 bore) is a precision-engineered engine component designed to restore cylinder integrity and extend engine life in small block applications. This replacement cylinder sleeve features a 4.120-inch bore diameter and meets the dimensional specifications required for Chevrolet bow tie block architectures, making it an essential part for engine rebuilds, restorations, and high-mileage engine remediation.

Manufactured from steel with a 0.076-inch wall thickness and 4.272-inch outer diameter, this sleeve is engineered to withstand the pressures and thermal cycles inherent to internal combustion engines. The 5.545-inch height accommodates the bore geometry of small block Chevy engines, while the tight tolerances ensure proper piston-to-cylinder wall clearance—critical for compression retention, oil control, and preventing blowby. The bow tie block designation confirms compatibility with classic and modern small block Chevrolet architectures, where cylinder wear or damage compromises ring seal and engine performance.

Engine builders, restoration specialists, and performance enthusiasts rely on quality replacement sleeves to recondition worn or damaged cylinders without full block replacement. This Darton sleeve is suited for applications ranging from stock rebuilds to performance engine builds where maximum bore diameter is retained. Whether restoring a classic muscle car, rebuilding a work truck engine, or refreshing a performance platform, precise cylinder sleeve replacement maintains compression, combustion efficiency, and long-term engine reliability.

Darton Sleeves is recognized within the engine building community for manufacturing OEM-quality cylinder sleeves that meet strict dimensional and material standards. Selecting the correct bore size and height is essential—this 4.120-inch sleeve is specific to applications requiring that exact specification, ensuring proper fit and preventing installation issues that compromise engine integrity.