It's been a while since I pondered over the details of those Kubota machines - back when I bought my JD 970 - almost 7 years ago, now.
If I recall, the 4850 is around 45hp and is a gear tractor. The 4350 is 4-5hp less.
Closest, similar sized JD machine in that vintage year would be the 1070 or the 990, I'd guess.
The 1070 is 38hp; 35hp @ pto with a 9x3 syncho gear box. The 990 is 40hp; 35hp @ pto with a 9x3 collar shift gear box.
The newest JD in this configuration is the JD 4005 model. It's rated at 41.5hp; 35hp @ pto and a 9x3 collar shift gear box.
IMO - the 1070 is the better machine of the 3 models. The 440 loader specs out just a bit stronger than the 300CX and the 3pt hitch is more capable as well with draft control as well as position control. In addition, the synchro tranny is a superior configuration over the collar shift - especially for loader use - 'cause you don't have to live and die with just 1st gear and reverse!!!
AKfish