They range anywhere from $500 to $2500 used depending on condition, new they are about $7000. Be sure to check the push bar and sickle bar for any bending or cracks as they are each about $1000 to replace. NH parts have gotten very expensive lately for some reason. However, the NH sickle bars are still some of the best ever made IMO. I have both a 451 and an old 450.
It is not hydraulic lift, it uses a wishbone linkage that connects to the top link to raise the sickle bar. It will take some adjustment to fit up to your tractor, there are some fitment issues on smaller compact tractors but it should work well on a JD 5303. The range of lift is variable depending on how you set it, but about 30* below to 30* above horizontal is about average. It is a pitmanless drive so it will run at steeper angles than that however.
