I think to answer your question, the condition of the spring eye bolt & bushing, the shackle bushings and pins and if any leaf springs are cracked or broken must be determined.
"Hoppy" might be related to the shocks.
I replaced the front leaf springs, rebuilt the shackles and installed new shocks on the '54 3100 last winter and Oh what a difference it made.
My words of wisdom; be sure to end up with made in the USA parts and do not fall for the cheap Spring Eye bolts.
Good luck
