Crane ( Ductile Iron ) rocker arms

Maybe so but overhardening would cause the balls to snap. Underhardening (soft metal) which I've experienced causes premature wear thus metal shavings. Both were problems. Most all the problems stemmed from product produced offshore. Just because it says "Made In America" doesn't mean the individual components were. Best solution for the op, buy adjusters from Smith Brothers for piece of mind.
I assure u I will buy 2 sets of replacements when I get the correct part numbers thanks for all yalls help and by possibly preventing me from ruining my engine .