904 Governor Replacement

and that answers the full manual question.
My First Trans-Go shift was a comprehensive all-modes kit. You could select full manual, semi-auto, and a modest bang-shift mode, from the instructions.
well of course, being a newbe, and like 24 years old, I went with the full-manual. Well that lasted about a week, maybe two.
Thankfully, at that time, full manual was reversible to semi-auto, pretty easy.
And since I had not changed the rear gear yet, the governor still worked pretty good. A lil tweaking and she was good to go.
I have never used a full manual since, lol.
My cars are usually DDs, and in city driving back and fourth to work, that manual shift was cutting into my girl-watching time. never mind; traffic lights, stop signs, and watching out for other idiot drivers doing what I was doing. lol.
Eventually I moved out of the city, and went back to a manual trans. I have a few of those to choose from.
BTW 3.55s are an excellent gear for an auto car. especially a city car. They have always been my go-to gear, since 1970.... albeit usually with a manual trans.