With hnsearch.com being shutdown, I believe he is referring to: http://hn.algolia.com/api
Also, you can set hitsPerPage = 1000. ;)
"you can only fetch the 1000 hits for this query, contact us to increase the limit"
It was a nice try, but it did seem too good to be true.
Just pass created_at_i<X, where X is the time stamp of the earliest submission.
I was able to download 500k stories (i.e. about half of HN's 1.26M stories) before I ran into memory issues; I've fixed them and am downloading the rest.