I had the cam nitrided in my 523 stroker. I'm not positive but I don't think we did the crank. It's a forged stroker crank and not an offset ground nodular iron. Anyone??
I just had 2 stock cranks shot peened and ground, supposedly improved the molecular voodoo baloney, I dunno. nitrated or cold case, ( if I'm correct) is surface hardening , usually only few thou deep, (.010-.020) but is supposed to offer a harder surface, more resistant to damage,
I would look into cryo-treating. This is what King did with my custom billet crank rated for 2000 Hp. Two rounds of -300 in between machine work. It aligns all the molecules. Just keep in mind you need to at least check so the specs after you do this as it will likely need machine work after.