3.23 or 3.55 Behind a 318

904/999 torqueflite

My transmission isn't done yet but I went with the 2.74 first gear and a 1.52 second gear in the transmission. Even if you don't know anything about transmissions
In my opinion. It's easier and cheaper to change out the transmission gears than it is the differential.

This lets you keep highway 1:1 gear.

I think a 2.94 gear with the 2.74 transmission gear will give you a 3.60 gear for take off and a 2.94 gear for highway.

There is a calculation where it shows you what it would end up as.