GM LS Dished Piston Set 4.070 Bore -20cc

The GM LS Dished Piston Set 4.070 Bore -20cc from Race Tec Pistons is a complete eight-piece forged piston set engineered for General Motors LS-series engine builds requiring precise compression control and optimized combustion chamber geometry. The dished design reduces compression height and increases quench clearance, making this piston set ideal for forced-induction applications, stroker builds, and high-RPM performance where detonation control and thermal management are critical.

Each piston features a 4.070-inch bore diameter sized for oversized LS cylinders and incorporates 1.5 x 1.5 x 3.0mm ring grooves, a configuration that balances ring seal efficiency with structural durability under sustained boost and high-load conditions. The -20cc dish depth reduces chamber volume by design, raising effective compression ratio without requiring block modifications—a critical advantage for turbocharged and supercharged LS platforms where compression ratio directly impacts power output and knock safety margins. Race Tec's forged construction provides the strength needed to handle repeated detonation events and sustained high-cylinder-pressure cycles inherent to boost applications.

This piston set suits engine builders and performance enthusiasts undertaking LS engine rebuilds, turbo and supercharger installations, and stroker combinations where factory piston geometry no longer matches the application. Whether building a road-racing LS, a street-strip twin-turbo platform, or a high-compression naturally aspirated engine, the dished design and oversized bore accommodate the aggressive specifications modern LS builds demand. Complete set of eight pistons eliminates the need to source matched pairs separately, simplifying procurement and assembly scheduling.