speedometer cable in 1961 F100

[chisum5013]

I am trying to replace the speedometer cable that was not working in my 1961 ford F100 pickup, but everywhere I go (part stores) they try to tell me that this is the right cable for that year and model. Please see attached picture and tell me if I am missing something, they don't look the same and I can not get the gear to slide in the new one. Thanks for your help in advance.