I am fairly sure that the shocks will bottom out before hitting the shock stops. They are a tad bit long if you go from the 4" to the 2" blocks. I think you will need the Motorcraft CK05TIC which are 1 3/4" shorter. I installed Rancho's and they didn't have, at that time, a shock that would be the proper fit for the 2" blocks. I spent many hours on the line with the Rancho customer service dept. I ended up retrofitting the axle shock brackets to give me an extra inch and used the longer shocks.
Don't take my word for it, do some careful measuring and I think you will find what I'm saying to be true.
Jim