I show on a reference on 1940 populations that Oak Park had 1,169 people. The Census Bureau has reports of population figures at: https://www.census.gov/library/publications/1942/dec/population-vol-1.html but I don't think their resolution/tables are for communities of that size. But see the reference I cite.
With only two 1940 ED numbers, you could patiently go through the entire sheets and with a spreadsheet come up with all sorts of information. I see on our https://stevemorse.org/ed/ed2.php?year=1940&fromEdFinder=yes&state=MI&county=All+Counties 1940 location tool... pick state Michigan and pick City or Town 'Other (specify) and then entering Oak Park,..... the following ED... 63-152 and 63-153. To see their ED definitions click on "More Details" .... The ED numbers are links to the first page of each of their sheets. 63-152 is the Village, and 63-153 is outside of the village but close to it.
