Correct Brake Booster
 

Ok now I am getting ready to take off my brake booster and I was going to send it out to get cadium plated, but upon looking on Ebay there is a bunch of ones pretty cheap that have the Delco Stamp on them. I must admit these are kind of looking like the way to go, any ones to stay away from.

I use one, no problems except that I had to change the pin going from the booster to the master cylinder to the original one.
The repro one was 1/4" to long so the brakes did not release completely.

If I remember right I got mine from PY by the way, and no stamp since the original one did not have it.