Jonald, you might want to do a bit of checking before ordering that fan to check on the diameter. Your '57 would have come from the factory with a 20" four blade fan with a 5/8" hub. Earlier 235's and 216's came with smaller diameter fans and 1" hubs. The fan shown on that link has a 15 3/4" diameter and is listed for a '47-'53. I'm not sure what diameter fan the 54/55.1's used, but you might want to check.
If you do open up the hub of your existing fan, I suggest doing it with a step drill. That should keep you centered. Harbor Freight sells a large one that would do the trick if you don't have one or don't have access to borrow one.
https://www.harborfreight.com/2-pie...-high-speed-steel-step-drills-96275.htmlMatt
