One concern to consider from an availability perspective is high strength jam nuts are rarely available. Designs with high strength fasteners are often assembled with the high strength nut against the bearing surface and the jam nut tightened on the standard nut as locking device.
Here are several useful web based tools related to bolts.
Bolt Stress
http://www.turula.com/bolt.html
Bolt Weight
http://www.portlandbolt.com/bolt-weight-calculator.html
Connection Calculator
http://www.awc.org/calculators/connections/ccstyle.asp
Bolt Ultimate Strength...
Each grade and manufacturers unique identifier must be marked on the top of head. Both specifications state that bolts which are not marked "shall be considered nonconforming and subject to rejection."
A325 Head Marking
A490 Head Marking
Just to reiterate what has already been said above; A325 and A490 structural bolts are VERY different both from a chemical and mechanical standpoint. It is improbable that there would ever be a situation that these bolts could be dual certified. The load requirements of a full size 7/8" A325...
IFI states shear value is calculated at approximately 60% of the minimum tensile strength of the fastener. I believe AISI also covers this in more detail under "Cold-Formed Steel Structures to the AISI Specification."
Adam Oakley
According to ASTM A354 it specifies grade BD as an acceptable substitute for A490 fasteners over 1-1/2” in diameter or with nonstandard thread lengths. A490 and grade BD have identical minimum tensile and yield properties. Grade BC has higher mechanical criteria than A325 and covers fasteners...
