Special is different , Super and Roadmaster are the same 51 52 . The same differences apply to 53 Bill
I would say that a 52 Roadmaster is unique to the larger 320 engine. There are likely 3 hoods for 51/52. Special, narrower than Super and Roadmaster and then Super and Roadmaster differ due to length. 53 Super and Roadmaster were a one year only hood as they were both V8's. 53 Specials still had the straight 8 and a narrower body. Gary