Exchange 3-speed manual for 904

Hi!

I want to swap the 3-speed manual transmission in my Dodge Dart 1963 wagon for a automatic one.

Questions:

1) Are they about the same length, or do I have to something with the driveshaft?
2) It's very important to keep the steering column shift arm (I am 6 feet 5) so no floor shifter in this car. What do I need? A hole new column or only shifting mechanism?
3) Is there any good shop manual for this car btw?

Kind regards /Peter
I'm in the process of swapping the slant/904 out of CUDAVRT and putting in a 273/ 4-speed. I have everything you would need. Too bad Sweden is so far away.
Stroker