The following post has been deleted and I still want to refer to the information (it is in my favorites)
How long will I be able to see this post until it is permanently purged?
In the entire history of Stack Exchange, I've only ever seen two posts that have been permanently purged. One was the "boat programming" one. The other was a very contentious "how do compilers work" question. Both questions were asked on Stack Overflow; neither should have been purged IMHO.
AFAIK it is SE's policy to keep deleted records forever (my two examples notwithstanding). But there's not a lot of information in the post you referenced; it would be easy enough to copy it somewhere, just in case.