Forged pistons will not knock when cold, I have run them most all my life. Cast are good, Hypereutectic are good till they fail and ruin everything in your engine. I run ductile iron, moly filled top rings in everything. I have also run Chrome faced rings with good results. Speed Pro, Sealed Power, Hastings are all good names. I'm trying Total Seal gapless top rings in my street only 340 this time.