I've measured both of them- - - -can't tell any difference. They both have a 3/8-24 thread and they look exactly the same. I've never done a Brinnell hardness test, though. I use NASCAR type ARP connecting rod bolts in stovebolt rods by putting 3/8-24 Heli-Coils in the rods. That reduces the possibility of camshaft interference in a stroker engine.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!