Does anyone know the size and type of thread the nut is for the stud on the
starter motor solenoid( the stud where the batt. cable goes to).
No, but if you can get to a fasteners place, they should be happy to measure it for you
Try an M8, but not sure(approx size), it could be a 5/16, usually most starters are the same, so find a bosch starter at the wreckers, and they will probably just give it to you.