help with rear main bearing

[paige816]

I have a 1988 volvo penta aq131/275 that threw a rod. bought a donor motor same kind with bad rear main bearing.1st question can i put the bearing from old motor into donor.2nd questionhow hard is it to change bearing or do you have to change flange seal too. I never changed one on a 4cyl before. both motors are out of the boats any help would be apprecciated