The Kubota engine is 111 cu. in and puts out 37 horse but needs 2,700 RPM to get the 37 horse. The John Deere only has 98 Cu. in. but puts out 42 horse at only 2,400 rpms. The John Deere is a much higher performance engine for sure. However, the Kubota has 13% more displacement. Bigger displacement is important for a diesel. Im not sure what one I would pick. I have a Kubota 21 horse . It is a B7510, I have 999 hrs on it. It has been used very hard . One reason is cause it is too small for what I use it for. I cut grass with 60" mower and when it is heavy grass in the spring , it bogs a bit and also when I move heavy snow. Very tough tractor and was in the shop one time when it was new . Had it for 15 yrs.
Good point on the engine HP @ RPM's.
Another thing to check is what RPM's are needed to run a 540 PTO at speed.
My brother's JD is at 2500 engine RPM's.
