TRW forged pistons (340)

Just like cam technology, piston technology has come light years from when heavy forged pistons were the norm. So much more has been figured out about reciprocating mass and its effects than was known 30 plus years ago. As stated, if you have them, use them. But I tell you what. I'll be danged if I would buy them. And I am also a big fan of hypers. Almost without fail, if they have a failure, it is due to incorrect ring gaps. They have very specific ring gap specs and they must be adhered to......at least the KBs do. The Speed Pro hypers do not require special ring gaps.