I would sure look at a good local spring and axle shop. Most all of these shops buy 5160 or 4140 steel and make wonderful springs at a fraction of the cost of "store bought" spring sets. I suggest you contact LH Threaded rod and Triangle spring company and they can direct you to the closest spring shop in your area. I had a complete set of springs made for my 68 cougar that I restored at substantial savings. A good spring shop can duplicate any spring that ever came down the pike. Good Luck.