There is a chart on page 158 of Wick Humbles book, How to restore your Datsun Z-car, that lists the torque specs for the various size and grades of bolts used on the car. He states that the ISO grade is embossed on the bolt head.

FWIW

Todd

Those are the ones I'm talking about webdawg.....Let's see if anyone has figured this one out. One of the serious historians should know this one.