Just peeling paint. Them engines are good for a long long time.
Similar outwardly to a B series, except that "hump" in the block below the filters, to make room for a longer crank. Overall length is even the same. Think it's called the C series, only made a 6 cylinder, the B series had the 4 and 6.
Have a friend who sells used equipment and he says it's easier to sell a 10,000 hour Magnum (which use the 8.3) than a 2,500 hour JD.