Z Bar ?
On my A-Body, there is a bracket and spacer that bolts to the two tapped holes in the bellhousing right above where the starter goes in. It hangs the pivot ball right out about where your picture shows you need it to be. I am looking for a picture of it online, but haven't found one yet. When I take measurements at home tonight, I will take a picture of the brackets and an old bellhousing to show how it is supposed to go.