The Italian Job---sung by Marlena Shaw
No, California Soul was sung by Fifth Dimension in 1969. It was not Nancy Wilson.
Marlena Shaw
The Gerald Wilson Orchestra did, and Marlena Shaw did. The latter is available on one of the Verve remixed/unmixed compilations. The Gerald Wilson version is hard to come by.
I don't know about Marlena Shaw, but Nancy Wilson did; and it's a classoc.