The acetate was discovered by moi in 1977 when I cleaned out April Blackwood publishing's office.
The identity of the artist is Van McCoy. He sang lead on most of his song demos. I still have Van's demo of 'I Get The Sweetest Feeling'.
From the same haul, I had other crackers such as 'Standing In The Need of Love by Francine Barker of Peaches and Herb.
I sold the ' I Go Out of My Mind' to RS around 1978 ish along with Johnny Honeycutt and the Cashmeres.
Goldsoul's post in Chris Bartley-Going Out Of My Mind was marked as the answer