Hypereutectic Piston Set, 3.940-inch Bore

The Keith Black KB399-030 is a set of eight hypereutectic pistons designed for Small Block Mopar engines. These pistons feature a 3.940-inch bore and a ring groove size of 5/64 x 5/64 x 3/16 inches. They also have a plus 6.00 cc volume.

Constructed from a high-silicon aluminum alloy, these pistons are lightweight to improve throttle response and RPM changes. They are engineered with race-ready features such as high upper compression-ring locations, gas-accumulator grooves, drilled oil returns, and spiral-lock retainer grooves, making them strong enough to withstand high compression and temperatures.