Here's a little connection: Helen recorded Mac's song "I Believe in Music", which didn't go anywhere. However, the B-side, "I Don't Know How to Love Him" (from JC Superstar) was a big hit for her in 1971, a year before "I Am Woman".
I seem to recall most of her songs from the 70s from her Greatest Hits album.
Anyone remember "You and Me Against the World" (with her daughter Traci)? Or "Ain't No Way to Treat a Lady"?