SBM Domed Piston Set 3.940 Bore +6cc

The KB PERFORMANCE PISTONS SBM Domed Piston Set 3.940 Bore +6cc is a hypereutectic small block Mopar piston set engineered for street and bracket racing applications. This eight-piece set delivers the precision geometry and controlled dome configuration necessary for increased compression while maintaining the durability small block builders require across a range of fuel types and ignition timing windows.

Each piston features a 3.940-inch bore diameter with the factory-correct 5/64 x 5/64 x 3/16-inch ring groove specification for small block Mopar compatibility. The +6.00 cubic centimeter dome volume raises compression ratio without requiring custom block work, making it an accessible upgrade path for builds targeting improved combustion efficiency. KB's hypereutectic casting process delivers superior thermal properties and dimensional stability compared to standard cast alternatives, reducing piston rock and extending service life under load cycling. The domed profile directs flame propagation more efficiently, aiding horsepower development across the midrange RPM band where street and bracket cars operate.

This set suits builders restoring or modifying small block Mopar engines—440, 400, 360, or 340 platforms—who need verified OEM-pattern pistons without custom sourcing. Bracket racers appreciate the consistent compression gain and predictable detonation curve the +6cc dome provides. Street enthusiasts benefit from improved volumetric efficiency without requiring fuel upgrades or advance curve modifications. Each piston is individually precision-finished and ready for installation into prepared block and rod assemblies.