LA small block,Do you put an oil passage in your head stud?
Oh I like that . it sounds like a right cross to the mouth in this conversation!
Not intentionally.
There's been lots of theoretical talk, but numbers make it real. Grain structures, surface hardness, metal treatments - they all matter when developing a system. But every system has some tolerance built in it.
A 1/2 head bolt can generate ~13k lbs of clamp load at 80lbs torque, lubed (120lbs dry). That 13k lbs equates to about 92ksi of tensile stress in the shaft of the bolt. ARP advertises 180ksi min strength for most of their fasteners, and as high as 220ksi.
That means in most cases, head studs are probably barely over 1/2 their design strength. Arguing over taking 2.5% away from their 200% FoS (factor of safety) is picking fly poop from the pepper.
ARP2000 is advertised as a superior material to 8740 CrMo steel. 8740 is a through hardening alloy, not a case hardening alloy. High alloy steels are often designed to provide ductility (bend before fracture) at extremely high stress levels. This means that though the material grain condition is important, the 'skin' of the material isn't. A cross-cut or spiral cut along the length might cause a problem, but a single axis-parallel groove or flat isn't.
