Kohler KT740 in a Gravely ZTR

[67Camaro]

We have a Gravely ZT 52 zero turn mower we got for cheap. The previous owner "hit something" with it and it died. He then dragged it to the garage. Hydro uniits are free but the motor is definitely locked up. Are these motors relatively easy and economical to rebuild or is it better to just buy a replacement? If I would want to buy a replacement engine, where is the best place?

 

[ILENGINE]

Hitting something causing the motor to lock up seems odd. More like a major failure of the engine like lack of oil and it sounded like he hit something when the factory smoke was expelled. And they are not economically rebuilds. And the best place to purchase a new engine is from the local lawnmower repair shop.