torque tube pinch bolt grade, strength
 

WSM says torque to 35 ftlb for 8 grade bolt, 58 ftlb for 12.9 grade. I have 2 new black 93142124000 bolts how do I determine which grade and hence what torque? '78 US 5 speed.

The two pinch bolts in my automatic model GTS torque tube have that part number and they are torqued to 58 ft lbs or so I seem to remember.

Porsche issued a TSB to up the torque on the pinch bolts,
add 10% to the standard requirement of 58 ft/lbs.

So torque the driveshaft pinch bolts to 66 ft lbs add a drop of blue threadlocker to the threads.
the bolt may have 12.9 stamped into it this is the bolt strength grade, this is what it should be,
best bet post a picture of the bolts you have

yes you could assume that if the bolts look like the each other