As the F100 had the Ford 9 inch in non limited slip applications, one from 57 to 60 would definitely fit, as would the corresponding Dana axle with limited slip from those years. It is also said that a 9 inch from an F100 through 68 would also fit. The big thing is that the spring pads on the replacement axle be the same distance apart as the old one and the end to end dimension be close to the same.

It is not too common for an axle tube to break, but I have seen it happen due to too many oferloads over time.