I use 2wd Chevys 3 leaf and half of the overload, that gives you about a 3" lift. If you need more to match your front springs, WELD a 1" block to your perches. I built my perches out of 2.5 x 2.5 x .250 square tube and designed the 1" lift into the perch so its one piece then boxed the ends in.
