Late model FSJ front leaf springs are similar to YJ lift springs. Only difference is that FSJ springs like the ones we have are a little bit longer in overall length. But more importantly the centerpins are offset a couple of inches from the center (top), while YJ leafs have a truly centered centerpin (bottom). That means installing these in place of YJ springs will move the axle two inches forward or backward. Our plan was to use the main and second leaf from the FSJ pack supplemented with four other leaves borrowed from some spare YJ lift springs we had. This should allow us to stretch the wheelbase of our Willys that used to run 3.5-inch YJ lift springs.