I dont feel like going out tonight and mesuring but I do know that the rear springs of my 85 p/u 4x4 are going up front for my SAS and will move th axle forward 2" from stock IFS.
You can gain more through the placement of you r spring hangers as well. I believe the length of the 85 springs are 46" eye to eye, but not positive.
I could take some mesurements in the morning.