I got some decent 52s from a real clean 90 k5 with 100,000miles that probably never towed or had weight in it. Well i got them in my 85 m1008 and they are real flat, they only have 4 leafs plus the overload. Not sure how much up travel i could possibly have from them without them negative arching. Just trying to figure out how others are, its looking like I might need to a add a leaf which will cause other problems, bc I already have a zero rate so the pack is pretty thick. My spring plate is really close to my pitman arm and I had to get a new steering arm so my draglink wouldnt hit the spring pack.