The John Deere 4010 was tested at the Nebraska Tractor Test Lab soon after it was introduced. The 302-cubic-inch LP-gas and gasoline engines developed 80.6 and 80.9 PTO horsepower, respectively.

WILLMAR, Minn. — Handling the threadbare ledger with care, Charlie Haug points to the handwritten script documenting where his great-grandfather sold a brand new 1961 John Deere 4010 tractor ...