what size of motor for belt conveyor?

i am looking at purchasing a hammer mill crusher. powered by a 6-71 detroit but the feed conveyor and exit conveyor were powered my hydraulics off the 6-71 but the previous owner stripped te system off, any ideas on what to use to power these conveyors,, feed hopper conveyor is 24 in x 10 ft the exit conveyor is 24 in by 25 ft ?



thanks