Mine is a 1982 K20. My first "lift kit" was a 4 inch pro-comp about 3 years ago. It road fairly decent, better than stock. It consisted of front springs, steering arm, u-bolts, rear blocks, ES3000 shocks and other hardware for about $450.00. I added swaybar disconnects and I was very happy with it. About 1 yr later, I installed an ORD shackle flip ($185.00) in the rear for a total of 8 inches with the blocks. For the front, I used Superlift 8 inch springs ($235.00), a Skyjacker pitman arm ($75.00), and Pro Comp ES3000's ($120.00) all around. I ended up having warranty issues after a year with the Superlift springs (sagging and broken center pin.), so 4 Wheel Parts in Reno exchanged them free of charge. When I replaced the springs, I added ORU 1 inch lift shackles ($50.00) up front.
Most people say my truck rides rough, but I am used to it. It flexes pretty decent. Even with 9 inch lift in the front and 8 in the rear, the rear still sits 1-1/2 inches higher so I will probably go to 8 inch bds springs with zero rates and my shackles in the future. I am not sure that I would use Superlift springs again, but I was very happy with Pro-Comp products. But no matter what you do, add swaybar disconnects to it, they are the single greatest ride improvement that you can do.