I had the same (I think) noise as you! It turned out to be the shocks where they attach to the LCA's. The bushings had worn out and allowed them to move up and down, causing the popping noise.
sounds like you did what I did when my 80 had a pop in the front. if its a nut or bolt, tighten it. Mine ended up being the front sway bar bracket on the driver's side.