The Mac II had a 5.25" half-height drive. The full height 5.25" drives are around 3.5" tall, I still have a Maxtor 1GB SCSI full height, it sounds like a 747 taking off.
You could make a bracket out of some angle stock, or just see if the threaded mounting holes on the bottom of the drive happen to line up with the grid of slots in that metal plate and mount it that way.
You could make a bracket out of some angle stock, or just see if the threaded mounting holes on the bottom of the drive happen to line up with the grid of slots in that metal plate and mount it that way.