Look up Aldo, aka the NJ steel baron. Best steel and prices you're gonna find on the www. Leaf springs can be great, but they're still a bit of a crap shoot. They may be 5160, they may be 4140, and they may be something else. Most American made vehicles from the 50's and 60's will have 5160 leaf springs. Of course, you still have the stress issue to deal with.