I found the Weston reference to la puta negra. It is in Charis' book, Through Another Lens, and she says Edward named the 1938 Ford sedan la puta negra, (the black whore) because he said any car that was in association with them must have a checkered character. She says soon they changed it to "Heimy" because it took too long to explain the other name.
There's a picture of their car in Golden Canyon, and indeed, it's the cheaper standard model, like mine, theirs being a tudor sedan and mine a coupe of course. I wonder if they bought the V8-60 model like mine in order to save even more $$.