Perhaps one of the most hardest items to replace from the manufacture of any furnace is the "Blower Cage" Wheels & Motors are not a problem. Manufactures do not publish any specs on the cages itself with that being said 99.99% of the time you don't replace the cage.
Unless yours has been stolen or rusted out from flooding- in that case "You're in Trouble" This blower cage came off a Nordyne product and knowing that can be very helpful. I have many cages but there are a thousand different configurations. Once the cage has been removed and if its not marked as to who -how-where-what and why it almost impossible to tell the manufacture.