73 Duster Pitman arm removeal(what size socket)

Trying to remove the pitman arm on my 73 Duster, but not sure about the size of the nut holding it on.Tried sockets up to1 1/4 but still to small.Everthing bigger is too big to fit. I'm guessing its a 1 5/16 or more.Just wanted to find out exactly before i go and buy the wrong size socket.I'm installing the Flameing River steering box on my car to replace my leaking worn power steering.I have the extension for the steering shaft and bought a new pittman arm from SPRINGS &THINGS that is supposed to fit.

Should be 1 5/16" socket for that pitman arm nut. Good luck! :salut:

O.K. Thanks for the reply I'll get a 1 5/16 socket.