I cannot say for sure it will work or not, but I do know a lot of the LX series skid steers used motors from other makers than NH
so might want to look into other like models, either a size up or down from your machine and see what powers them!
and thee guys seem to be able to get one for you if needed?
LX665 Complete Engine for sale at AMS Construction Parts. This part is for a New Holland LX665 Skid Steer part number
amsconstructionparts.com