340 head torque requirements

Bewy said
15 ft/lb on the rocker shaft bolts. Can be grade 5 or 8.
That is because they are not being torqued to the max available for that diam bolt. ARP lists 5/16-18 torque varying from 26 to 32 depending on bolt grade.
Tq is low because you are tightening on a hollow tube that can get squeezed out of shape with excessive tq. Not a problem with stamped rockers, but could bind up other types.

I would agree. Am using Hughes Engines shafts so do not thing deformation is an issue. The debate is what torque value is acceptable for grade 5 vs. grade 8 to achieve the proper stretch and clamping force. I plan on installing my head bolts dry to achieve the 95 ft.lbs requirement (106 max). If oil is used on threads, clamping force is limited to 80 ft.lbs.