1975 Dart Manual steering conversion

I'm looking at converting my power steering to manual steering. I know that in order to use my current centerlink I have to find a 73 up manual gearbox. I'm a little confused on the sizes. What is the diameter of the pre 72 output shaft vs the 73 and up output shaft on the manual box?
I found a gearbox on Ebay and a guy sent me photos of the output shaft at 1.1 that is dia of the power steering gearbox output shaft!?! Help explain all the different sizes please.