[Cub cadet 782d]

I recently bought a 582 for $200 and the engine was out because the previous owner said it blew oil through the carb. So my question is should I rebuild the motor it has been sitting for a while and there are mud dobbers(wasp nests) in the motor itself and it is missing some parts, or should I be looking for a motor to replace the old one. What would be a good motor to put in it that will bolt up pretty close the the original. Thanks.