Confusion about 833 4 speeds

So I have this 4 speed trans with a date code of 10-18-66. It has a 26 spine output shaft that connects to the drive line. The Duster I have currently has a OD Trans and it has a 30 spilne output now. The problem is obvious, when I install the 4 speed I would not be able to connect my drive line unless I get it reworked with the smaller yoke, bad Idea I think?

Can the 4 speed be converted to a short shaft 30 spline tail shaft. I think this is the main shaft from what I have read but not sure>

What do I need to get to convert. I plan on rebuilding the 4 speed before installing it and would like to keep the 30 spline drive line yoke.