If ya can't find a set they are easy to make.
Take your spring seat washers (top of strut seats on the inside, bottom of spring on the outside) to a machine shop and slice them at the side of the step into two pieces. Then have them cut you the proper diameter tube to lengthen the step and weld them back together. What ever length you add is what the drop in height will be. Can be done at home with hand tools too but you can get a straighter job done with a lathe.
opsled