anyone running ross piston

KB is fine. In fact, those of us running 440 Source forged pistons are made by KB too. Hypers do fine if the piston to wall is right at the beginning. It's tighter than any cast, and way tighter than any forged piston's wall clearance. If they are lose in the bore, the rings dont seal. But the piston doesnt come apart. Least none of mine have at 40K plus. Ross has had some issues but in general they make a nice piston. If I want a good piston, I use Diamond. Any 4" engine should have a good forged piston IMO. And Diamonds are always dead on in all ways.