I had an open diff when I got the car - and it was real good if all you wanted to do was spin one tire. I now have a Torsen-type differential (Powertrax Grip Pro
WELCOME TO POWERTRAX - Powertrax ) and it is fabulous. These are available for Dana 44, but only ratios 3.92 and up. Most major manufacturers now offer Torsen-type differentials, including the very popular Eaton Detroit Truetrac.
It's worth noting there are different units for axle ratios: a) 3.73:1 and down; and b) 3.92:1 and up.