100 inch pounds is probably for the tin pan that covers the bottom of the bell housing. That's probably about seven foot pounds (I didn't do the exact calc)
You can measure the size of the bolts for the pressure plate, (not the wrench size) and Google max torque for that size bolt.
Edit: if that's not a blind hole (I don't think it is) trying to drill it out for an easy-out might push the busted bolt out the back side!