I love John Deere combines too. Well maybe not enough to have one in my avatar. But, they do have a link to hotrods.
The Model 55 combines have steering drag links that are the same as mid 30's to early 40's Fords. And if you need a 12 inch pitman arm for your side steer "T" Track Roadster so you can cruise the Salt Flats, Old John will gladly give up his parts. I'm sure if you study the anatomy of the John Deere you will find many potential hotrod parts lurking in the big Green frame.
Tom knew that the mid 60's self propelled John Deeres would occationally be equipped with a sealed motorolla alternator (about 30 amps). A trip to the alternator repair shop, and the promise of cash, yeilded this "gem" of a hotrod accessory.
It was ugly green and connected to a remote regulator. The alternator guru replaced the bearings and a diode and installed an adjustable output mini regulator and converted it to "one wire" operation. Parts about $55, Labor about $38, Alternator saved from the recycler about $15. A Little over a 100 bux and we are combine "COOL".
If you didn't "thrash" it with your own hands-you didn't really "combine" it.