Good job on your find. It looks as though you didn't need our help after all! LOL
If I remember right, the semi float axles are around 65" WMS. It should work pretty good. The 3.73 gear should improve your cruising speed dramatically, without taking away the low end.
For your rims on the back, try to look for some Dodge B3500 rims. In my junkyard exploring I've found that they have a little more backspacing. For the front rims, look in the Ford direction. The ones I have on front fit perfectly.
