Hello mjgord,
If your Unisaw has an oval opening for the motor. You have what is called a repulsion induction motor. It is a older style motor which utilizes a armature,field and brushes. Almost round in shape.You probably have no chance on finding a motor like that. You can use the motor that Rockwell/Delta has using for years, it is part number
438023146201. If you have the old style cabinet with oval opening you will need to make it a square opening to allow for the new style motor.
Hope this helps,
-WJA