Sorry to bump but...
I installed the Edelbrock shocks last night. Fun stuff! The new hardware and bushings are definitely an improvement over the old. Fairly painless install overall but I learned some new tricks...
Anyways, the shocks that arrived were IAS ("Inertia valve") controlled that supposedly vary dampening based on speed of shock action, so street dampening is stiff and offroad is plush.
My old shocks were Motorcraft units, possibly factory. All felt a little squelchy and one had no rebound. The new shocks are STIFF. Compressing them took some muscle and creativity. Comparatively, the ride now feels a lot more composed. Before when I went over bumps the whole car would rock and roll around. There was dampening but... too bouncy. Cornering was good, though the body leaned a lot. With the new shocks I certainly feel a difference. Bump damping is far improved and the truck feels more stable now. On asphalt, I can corner even harder and the truck stays level.
Only thing left to add... compressing the rear shocks, even with suspension extended, was a pain. I mounted the top bolts and compressed the shock while a friend put a screwdriver through the lower mount and then drifted in the bolt. To get them compressed and then swung into the mount, I tied an old tie-down strap onto the shock's lower boot retaining ring, and looped the other end around the crossmember and back down. With my friend applying tension to the strap, I could compress the shock a little at a time and have him hold it from extending again as I rested my arms, and then it was easy to work into place. The front shocks were done using a loop strap included with the shocks to hold them in the compressed position.