Head and cam selection help for 440

what is the benifit of a light rotating assembly? I know it will rev quicker but i have heard many times that it doesnt really make it faster.. I just remember years ago when i built this thing, several people on moparts ragged on me for using such heavy pistons, and then not rebalancing it..I think hearing all that back then has haunted me..lol..here lately though i have had it out every weekend giving it heck and having fun!
That's why all the racers use the cheap heavy **** because it doesn't matter. Apparently you have never heard of parasitic power loss.