In my humble opinion, the easiest way to get to the right map is to use this search link at stevemorse.org. You simply select the state, county, and city in which you are interested and you will get a list of links to the available 1940 enumeration maps:
Turns out, the census enumerator wrote the wrong house number for the Licciardi family's address on the 1940 form. He wrote '3521,' which, if you look carefully, doesn't even fit the sequence of the other addresses on the page. And, upon further searching, I discovered that there isn't even a lot at 3521 MLK Jr. Blvd. Thank goodness for the city directory, which DID have the family's correct address (3591).
I HAVE located the home via Google Street View and will be talking about it in a separate post later this week, so stay tuned!