My dad really gets a kick out of old 2-cylinder John Deere tractors. He's always telling me how his father put him to work at 7 yrs old and he never got off one. His prized Model G was worn from 62 years of service, so he pulled it into the woodshed, took it down and rebuilt everything. He cast his own rod bearings, pressed in new bushings, sized them by hand, refinished the 6.280" cylinders and fixed the oiling system. I went through the cylinder head, refacing the 2.250" valves and performed a multi-angle valve job with port/chamber work. We also milled .125" off the cylinder head to increase compression. It's hard to comprehend how big everything is inside these things. This one is 413Cid and it's back up and running quite well!