In the late 90s my dad built a 440 using those pistons. Only got 2 races on the engine before a piston came apart while warming up the car on the track. Another friend racer of ours with a small block chevy broke a motor around the same time frame with the same pistons. Didn't hear much good about them so we always stayed away from them from that point. Than my wife was running her dad's car around 2014-15 and broke a motor in the burn out. Tore it apart and it had KB hyper in it as well. The engine had several years on it, but what was left wasn't pretty. Couldn't even find the 1 piston as it was in about a million pieces.