Quick Question: Replacing objects with blocks?

So what I have right now is a model consisting of a bunch of 3D objects, each created individually, but each identical (copies of the original object). I want to make a modification to all of them. I realized it probably would have been smart to save the object as a block. Is it possible to replace all these objects with a block that I've defined?

I'm using cut/paste as a block, by right clicking. Once you have one done, just do COPY command to replace everything else.

Then, you can use BLOCKEDIT.

There's more than one way to do this, but this is the one I use...