I have a '57 Ranchero with a 292.  The windshield wiper motor has 2 vacuum ports; one on the top, one on the bottom.  From which vacuum source does each port hook up to?

I have 3 vacuum sources on my carb and intake manifold.  A very small one on the body of the carb that goes to the distributor advance diaphragm, one on a spacer between the carb and the manifold, and one on the manifold itself.  Currently the manifold and the spacer are hooked together.  The wiper motor has nothing running to it now.  I also have a vacuum source on the top of the fuel pump attached to nothing.

Thanks for any help.

Bruce