Eric,

Good Grief! After reading your reply and as its significance sank in, I could never have slept without going outside in the dark to hold up my old box to the one mounted on my car. You have completely nailed it!

I would have never noticed the differences between the pittman arms of the 71-72 140 and a 74. My 74 box does have a different pittman arm from the 71-72 boxes I have had mounted. What a learning moment for many of us with aging 140's.

The diameter and thread of the Pittman arm shaft are the same. It appears if I can get the Pittman arms off, that switching the two arms will make my world start spinning again.

Do you have a favored technique for removing the Pittman arm from its shaft?

Again, I am grateful, humbled, and amazed by the knowledge shared by those on this forum.
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Antique Swedish Steel 71 142E color V#102