Do you mean a 4865? I don't recall a 4864, nor could I find a listing for one. If the 4864 is the same as a 4865, then its a good baler to stay away from. The 4865 was about the same baler as a Case 8480, only they seemed to be built a little lighter. They were prone to bearing failures and I've seen more New Ideas burned up than any other breed of baler. The pickups were not well designed and wouldn't feed properly in heavy hay or fluffy straw. The neighbor has a 3650 CaseIH (precursor to the 8480) and I'm constantly fixing that thing for him. The 3650 has a belt drive pickup, which is one of the worst ideas ever, and IIRC, the New Idea had that same pickup (you'll want to double check that though, my memory ain't what it used to be)
Do yourself a favor and find something like an M&W 5506 or even an older M&W 1800, if you really want softcore. I also see New Holland 654s (4x5 hardcore, about the same weight as you'll get from a 5x6 softcore) selling in that 7 or 8 thousand range in good shape.
Rod