Many years ago a friend of my Dads (Mopar dealer mechanic) ,if I remember right, he used the poly forged crank in a 340. But that was many years ago.
When I have time I will look up the specs on that
I was going to ask as well, I thought you sandblasted, very nice work. Did you put any type of metal prep on after you got it down to bear metal.
I remember my Dad would use some mynric acid sometimes on some cleaned up rust areas,