How old of a unit is this? Late 55s had the Deere 303 gasser (if memory is still working) and plenty of them hit the scrap yards. On my 6600, (329 cubic inch Deere) the fan belt came off and I melted a piston. I treated it right, went to the junk yard and bought a used piston with rings. Threw it in, ran 4 more seasons until I found a cheap diesel.
I would patch it up as you are lucky to get 100 hours on it a year.
$14,000 for an overhaul? You could buy 3 or 4 cream puff 55s for that much money.