Given it is a grader, not a tractor, I doubt you will find parts, with the exception of some parts that might have been common with tractors at that time, for it on this site. Even then, it will be a case of you needing to know what tractor to look at, to find the part you need.
If you post what parts you are looking for someone might have suggestions or give you ideas of what/where to check.
I will also suggest you try Minnpar. They have some AC parts catalogs free to use on their website and they have some parts for AC equipment. Some of the AC construction equipment catalogs will show as Fiat Allis. Here is a link to the AC catalogs on their website. https://www.minnpar.com/manuals3.aspx?FName=FIAT%5FALLIS%5FPARTS%5FMANUALS&SFName=FIAT%5FALLIS%5FMOTOR%5FGRADER%5FPARTS%5FMANUALS