I believe the bolt runs up thru the bottom and threads into the bell housing? Hardware store will have a grade 5 bolt that works. You need to determine length thru all the pieces including washers, the thread size and it should be a partially threaded bolt. If it's threaded all the way, It will possibly tear rubber unless there is a sleeve?
If its a thru installation with a bolt and nut, same basic as above, size, length, grade.
The AD guys will be your best info. Just letting you know that it's not "special".