BBC Domed Piston Set 4.125 Bore +17cc

The KB Performance Pistons BBC Domed Piston Set 4.125 Bore +17cc is a hypereutectic piston package engineered for big-block Chevy engines demanding increased compression and combustion chamber volume. This eight-piece piston set delivers the dome geometry and displacement characteristics required for naturally aspirated and moderately boosted big-block applications where additional cubic centimeters and compression ratio optimization are critical to peak performance.

Each piston features a 4.125-inch bore diameter with precisely machined ring grooves (5/64 x 5/64 x 3/16 inches) that maintain consistent ring seal and oil control across the combustion cycle. The +17.00cc dome design increases displacement per cylinder while raising effective compression ratio—a critical factor in gasoline engines where combustion efficiency directly correlates to horsepower output and fuel economy. Hypereutectic construction provides dimensional stability across temperature extremes and resists scuffing in high-RPM environments where aluminum-to-cylinder-wall contact is unavoidable.

This piston set is purpose-built for big-block Chevy engines in street performance, bracket racing, and vintage restoration applications where builders need precise bore sizing and dome geometry to hit target compression ratios. Buyers rebuilding BBC engines from the 1965–1996 generation benefit from the standardized 4.125-inch bore specification, which accommodates popular BBC block configurations and intake manifold combinations without requiring custom porting or bore modifications.

KB Performance maintains a strong reputation in the domestic engine-building market for tight manufacturing tolerances and ring-groove consistency. The +17cc displacement addition is a common specification in small-to-medium compression big-block builds where naturally aspirated flow and mechanical reliability take priority over maximum boost capacity. Verify ring compatibility, gudgeon pin diameter, and connecting-rod length before installation to ensure correct assembly clearances.