Block Sleeve - SBC 4.125 ID x 5.625 Long

The Block Sleeve - SBC 4.125 ID x 5.625 Long by DART is a precision-engineered cylinder sleeve engineered for small-block Chevrolet engine rebuilds and performance modifications. This component addresses cylinder wear, scoring, and damage by providing a reliable foundation for engine reconditioning without requiring complete block replacement. Whether you're restoring a vintage muscle car, upgrading a street engine, or building a high-performance racing platform, this sleeve delivers the structural integrity serious builders demand.

Manufactured to exacting tolerances, the Block Sleeve features a 4.125-inch inner diameter and 5.625-inch length, designed to accommodate standard SBC bore specifications and piston configurations. DART's manufacturing process ensures concentricity and wall thickness consistency critical for proper piston ring sealing, combustion pressure containment, and long-term durability. The sleeve's cast-iron construction provides superior heat dissipation and thermal stability compared to aluminum block alternatives, making it ideal for forced-induction, nitrous, or high-RPM applications where cylinder temperatures climb rapidly.

Enthusiasts tackling SBC engine rebuilds—from 283 to 400 cubic-inch combinations—rely on quality sleeves to restore worn or damaged cylinders without full block machining. This sleeve integrates seamlessly with standard small-block Chevrolet blocks, supporting everything from stock restoration to aggressive boost levels. Proper installation requires precision honing and careful piston-to-wall clearance verification; professional machine shop fitting is recommended to ensure optimal ring seal and bearing life. At 2.25 lbs, the sleeve's weight is negligible relative to total engine assembly, making it a cost-effective upgrade for any serious rebuild project.