little al, you would have to make no major changes from beans to corn, just fan speed and concave setting and sieve setting and rotor speed, depending on conditions and size of cornhead. Make sure 1680 has aleast 4 and upto 8 seperator bars on rear of rotor or will have alot of rotor loss in corn. Amount done in a day has alot of variables, size of head, unloading on the go, drieness of corn. But you would like the quietness and simplisity compared to a 7720