To be most unlucky OEI occur, so other engine take over. So Eng Torque will be same as Mast Torque (say at that time mast torque is 80), So Eng Torque = 80.
Keep in mind that mast torque is not the sum of engine torques. Engine torque includes losses due to driving tail rotor, electrical system, generators, etc. Mast torque is the torque actually applied through the mast.
The conversion factor between mast and engine torque is listed in the flight manual, but is slightly dependant on a number of factors.