Make sure it has a good axle and ratio in it. When I was looking for a V-10 powered Excursion last November through about April to replace my 1/2 ton pickup I had a hard time finding one with limited slip for some reason. You can tell by looking on the drivers door pillar. You can google the code to find out if its limited slip and if its 3.55/3.73/or 4.10 If you can not find it I have all the codes. Just post it or PM me. 99% of the time a Ford truck will have a two digit axle code and if its numerical only its NOT limited slip. If it has a letter then a number its limited slip.
Chris