pellmell Not a chemist or metallurgist or whatever, so don't understand what all that means. But, that blue head 919 was the hottest, longest of all of them. Of course, crazy bastage me sold it off as the longest driver I ever built. And it was a beaut with the blue HOF Whup N' Shaft.
I did make a killing on it via the sale though. Huge $$$, compared to what I had invested.😉