Need help with 1975 Duster /6 to 440 conversion

You may also want to consider snagging an 8.8 Ford from an Explorer, they often come equipped with 3.73 or 4.10 gears and trac-lok diffs. Becoming a popular swap as they are reasonably cheap and easy to find, will need to be shortened of course, but if you grab 2 right side axles you will be set. Added bonus is they already have disc brakes!

Do the axle tubes on the 8.8 just unscrew from the housing? And do they have any large nuts/bolts on those explorer rear ends, or is it all sub-1" metric and standard stuff? I'll probably head out to my local Pick n' Pull as there's about 25 explorers there with the 8.8.