Does anyone sell new super stock springs?

What's the reason of running two passenger side springs?? Are the driver side and passenger side made different? The reason I ask is I'm looking into new springs for my dart swinger I want to bring up the rear some and stock springs ain't doing it for me.
Super Stock springs have an extra leaf on one side. You can install 2 springs of the same number. either 5 or 6 leaf. ESPO can build you a set in 1 or 2" over stock. These are stock 5 leaf springs I installed 10+ years ago. Still working great! THey were from ESPO.

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