Clue 150 across: 40s US roadhouse brew.
Four letters ?A?A
I am assuming that because it has 40s that it is perhaps an illegal drink during prohibition - maybe slang. Java is too obvious.
Possibly mala - offenses against right & law.
Elizabeth, prohibition was well and truly over by the 40's. Java is most likely. There is also a very strong alcoholic drink know as MALA but unlikely it was sold in roadhouses.