Spring swap

[JPCY72]

Hey guys, I need your help.

I tried searchin and cant find anything on the leaf swap from 72 springs to the newer springs from 73-87 I read somewhere that they are bolt in... but the length puts the shackle at a better angle. I have a line on a set of 4 inch lift springs, my truck is a 72 k20 camper special and it rides really rough. My plan was to pull one leaf from the lift springs and I have a set of 56s 11 leaf set that are really soft???? but theyre from a 1 ton.....

Thanks guys...