I had a 1953 Chevy 3800 several years ago now...I took the whole rear springs and hangers and rear end out and swapped out brand new leaf springs from the fine folks at STS spring company they were originally found on like a 1998 Chevy 1500...
new rear spring viewI am not sure if this helped the ride or not but it still rode like a old truck to me...nothing like the way the new stuff rides for sure...
Good luck with finding the issues at hand...
MikeC