the front 4 shocks are all the same, the back two are taller.
I put a 4in Rough Country on my 85k10, rear blocks and new shocks. The front with new springs and four new shocks and the pit arm. I didn't extend my brake lines, for normal driving I have enough, even over curbs, but serious 4x4 you might want longer ones. Other thing you'll run into are the drain lines on your axle diffs, just gotta make a lower mounting bracket, you should see what I mean.
What does the 4in lift on your 77 have?
Also remember to drop your transefer case, and fix your front driveline