OD or Non OD 833 behind a slant 6?

I get what you mean by the od and final gearing. That’s why I have 4.88’s behind my t56 in my duster. I’m not trying to spend a grand plus changing out the rear just for gearing. I literally have everything to put either trans in the car so I’ll have nothing in it. Just trying to add the 4 speed fun to this car with what I have but wanted to make sure it was going to work before spent the time swapping everything.

But does the Duster have a slant six? What will happen is, with the OD, and possibly even the non OD, you will find yourself downshifting on the highway at the slightest little incline. This is especially true of the OD unit. By going with what most would consider "too much gear", you keep the engine in its designed power band longer and it is still in the beginning of the power band in OD. It will make for a much nicer driving experience.

I do tend to agree though, if you don't go with the lower gears, choose the non OD with the lower first gear set. Good luck!