Well, with Kubota, the difference between the L4330 and the L4630 which use identical diesels, is the fuel injectors as my dealer told me. Perhaps a quick trip and a look under the hood might reveal a little. Rockyridge has probably crawled all around his 4310 enough to give you a part number or description of the pump and injectors. My neighbor uses a JD 790. I think for it's size, the power is very decent. The exhaust blows in your face and smells like burning BBQ fluid more then diesel, other then that, it works just great for him. I've tried talking him into redirecting the exhaust pipe if purely for his health. I removed the loader for him. He was very reluctant to have it removed fearing it would never go back on. I told him I would also put it back on. He was quite insistent that it really was not a problem mowing with it on. He now can't understand why he ever mowed with it on. Sometimes you just gotta show these old farts a few things, after all, they certainly have showed me plenty, Rat...